AMERICAN  SCIENCE   SERIES 


BOTANY 


HIGH  SCHOOLS  AND    COLLEGES. 


BY 

CHAELBS  E.   BESSEY,   M.Sc.,  PH.D., 

I'ROKESSOK   OP    BOTANY    IN    THK    IOWA   AGRICULTURAL    COLLEGE    AND   LATE 
LECTURER    IN    THE    UNIVERSITY    OF    CALIFORNIA. 


THIRD  EDITION  REVISED. 


NEW    YORK 
HENRY  HOLT  AND   COMPANY 

1883 


Copyright,  1880, 

BY 

HEKUY  HOLT  &  Co. 


Presswork  of 

DANIEL  G.  F.  CLASS, 

17&19Ko8cSt.,N.Y. 


: 


PREFACE. 


THIS  book  is  designed  to  serve  as  an  Introduction 
to  the  Study  of  Plants.  It  does  not  profess  to  give  ik 
complete  account  of  the  Vegetable  Kingdom,  but 
only  such  an  outline  as  will  best  subserve  the  pur- 
poses of  the  work. 

In  its  preparation  there  have  been  kept  in  view 
the  wants  of  the  large  number,  in  the  schools  and 
out,  who  wish  to  obtain,  as  a  branch  of  a  liberal  cul- 
ture, a  general  knowledge  of  the  structure  of  plants, 
with  some  idea  as  to  their  classification  into  the 
larger  divisions  and  subdivisions  of  the  Vegetable 
Kingdom.  For  this  class  of  students  and  general 
readers,  what  is  here  given  will  in  most  cases  be 
amply  sufficient  to  enable  any  one  to  understand  the 
greater  part  of  the  current  biological  literature,  in  so 
far  as  it  relates  to  vegetable  organisms.  For  the 
student  who  desires  to  pursue  the  subject  further, 
or  who  intends  to  make  botany  a  special  study,  this 
book  aims  to  lead  him  to  become  himself  an  observer 
and  investigator,  and  thus  to  obtain  at  first  hand  his 
knowledge  of  the  anatomy  and  physiology  of  plants : 
accordingly  the  presentation  of  the  matter  has  been 
made  such  as  to  tit  the  book  for  constant  use  in  the 
Laboratory,  the  text  supplying  the  outline  sketch, 
which  may  be  filled  up  by  each  student,  with  the  aid 
of  the  scalpel  and  compound  microscope. 

This  book  is  an  expansion  and  considerable  modi- 
fication of  the  material  of  several  courses  of  lectures 


iv  1'liKFACE. 

annually  delivered  to  college  students.  In  general 
plan,  Part  I.  follows  pretty  nearly  that  of  Sachs'  ad- 
mirable "Lehrbuch,"  and  in  many  instances  it  has 
seemed  to  me  that  I  could  not  do  better  than  to 
adopt  the  particular  treatment  which  a  subject  has 
received  at  the  hands  of  the  distinguished  German 
botanist.  This  has  been  rendered  possible  through 
the  liberality  of  my  publishers,  and  the  courtesy  of 
Engelmann  of  Leipzig,  the  publisher  of  many  of 
Sachs'  works,  by  which  many  of  the  cuts  of  the 
"Lehrbuch"  are  here  reproduced.  This  book  will 
thus,  to  a  considerable  extent,  serve  as  an  introduc- 
tion to  that  work.  Free  use  has  also  been  made  of 
the  recent  works  of  De  Bary,  Hof meister,  Strasbur- 
ger,  Nageli,  Schwendener,  and  others,  to  whose  writ- 
ings numerous  references  are  made. 

In  Part  II.  the  general  disposition  of  the  lower 
plants  is  a  considerable  modification  of  that  proposed 
by  Sachs  ;  that  of  the  higher  plants  is  made  to  con- 
form to  the  system  of  classification  in  vogue  in  this 
country  and  in  England,  as  outlined  in  Dr.  J.  D. 
Hooker's  "Synopsis  of  the  Classes,  Sub-classes,  Co- 
horts and  Orders,"  in  the  English  edition  of 
Le  Maout  and  Decaisne's  "Traite  Generate  de  Botan- 
ique,"  and  as  given  much  more  fully  in  Bentham  and 
Hooker's  still  unfinished  "Genera  Plantarum."  The 
notes  upon  the  economic  values  of  the  more  impor- 
tant plants  of  each  order  are  based  upon  my  own  lec- 
tures upon  Economic  Botany.  I  have  also  freely 
used  the  similar  notes  in  Le  Maout  and  Decaisne's 
work,  cited  above  ;  Balfour's  "  Class-Book  of  Bot- 
any," Archer's  "Economic  Botany,"  Smith's  "Do- 
mestic Botany,"  Laslett's  "Timber  and  Timber 
Trees,"  etc.,  etc. 

Necessarily,  there  is  but  little  that  is  really  new  in  a 
treatise  like  this.  Aside  from  a  more  or  less  important 
and  original  arrangement  of  the  matter,  so  as  to 


PREFACE.  V 

secure  a  more  logical  presentation  of  the  subject, 
there  are  but  two  considerable  innovations,  consist- 
ing (I.)  in  the  recognition  (in  Chapter  VI.)  of  seven 
quite  well  marked  kinds  of  tissue.  In  this,  however, 
while  not  adopting  De  Bary's  classification,  I  have 
followed  his  method  of  treating  the  subject,  as  given 
in  his  recent  work  on  the  comparative  anatomy  of 
plants  ("  Vergleichende  Anatomic  der  Vegetations- 
organe  der  Phanerogamen  und  Fame.")  (II.)  The 
second  considerable  innovation  occurs  in  Part  II.  ;  it 
consists  in  raising  the  Protophyta,  ZygosporefiB,  Oos- 
poreae  and  Carposporese  to  the  dignity  of  Primary 
Divisions  of  the  vegetable  kingdom,  co-ordinate  with 
the  Bryophyta,  Pteridophyta  and  Phanerogamia. 
The  usefulness  of  both  of  these  departures  from  the 
common  practice  has  been  subjected  to  the  test  of 
the  laboratory,  and  the  lecture  and  class-room,  with 
the  most  satisfactory  results  ;  and  I  am  led  to  hope 
that  in  the  hands  of  others  they  may  also  serve  to 
give  a  clearer  and  more  accurate  notion  of  the  struc- 
ture of  plants.  Should  they  do  this  they  will  need  no 
further  apology  or  defense. 

Of  the  illustrations,  many  are  entirely  new  ;  many 
others  have  been  re-drawn,  from  various  sources, 
with  slight  modifications,  expressly  for  this  work, 
and  all  from  other  sources  are  specially  acknowl- 
edged in  their  places. 

I  desire  here  to  acknowledge  my  indebtedness  to 
Dr.  Asa  Gray,  whom  it  is  an  honor  to  own  as  my 
sometime  teacher,  for  kindly  aid  and  counsel  in  the 
preparation  of  the  lectures  upon  which  this  work  is 
based  ;  and  in  the  same  way  I  am  indebted  to  Dr. 
G.  L.  Goodale,  Dr.  W.  G.  Farlow  and  Professor  A. 
N.  Prentiss.  For  aid  in  the  immediate  preparation 
of  the  material  for  the  press,  acknowledgment  is  due 
many  of  my  personal  friends  :  Mr.  J.  C.  Arthur  fur- 
nished the  original  drawings  of  the  water-pores  of 


VI  PKKFAVE. 

Fuchsia,  and  of  various  tissues  of  Echinocystis ; 
Professor  H.  L.  Smith,  of  Hobart  College,  New 
York,  contributed  the  sketch  of  the  classification  of 
the  Diatomaceie  ;  Dr.  T.  F.  Allen  furnished  a  synop- 
sis of  the  classih'cation  of  the  Characese  ;  Dr.  B.  D. 
Halsted  also  furnished  material  and  notes  upon  our 
native  species  of  Characese  ;  my  colleague,  Professor 
W.  H.  Wynn,  kindly  determined  some  of  the  more 
difficult  etymologies ;  to  my  wife  I  am  deeply  in- 
debted for  efficient  aid  in  the  laborious  tasks  of 
proof-reading  and  indexing. 

Should  this  book  serve  to  interest  the  student  in 
the  study  of  plants  as  living  things,  should  it  succeed 
in  directing  him  rather  to  the  plants  themselves  than 
to  the  books  which  have  been  written  about  them, 
should  it  contribute  somewhat  to  the  general  read- 
er s  knowledge  of  the  structure  and  relationship  of 
the  plants  around  him,  the  objects  kept  in  view  in  its 
preparation  will  have  been  attained. 

C.  E.  13. 

BOTANICAL  LABORATOKY,       i 
IOWA  AGRICULTURAL  COLLEGE,)" 
AMES,  IOWA,  April  12,  1880. 


PKEFACE  TO  SECOND  EDITION. 

In  this  edition  a  few  errors  which  had  escaped  detection 
in  the  first  issue  have  been  corrected,  and  several  minor 
changes  in  the  text  have  been  made,  which  the  lapse  of  a 
year  and  a  half  since  the  manuscript  left  my  hands  rendered 
necessary. 

C.  E.  B. 

May  21,  1881. 


CONTENTS. 


PART  I.    GENERAL  ANATOMY  AND  PHYSIOLOGY. 


CHAPTER     I . 
PROTOPLASM. 

PAGE 

General  Characters — Chemical  Composition — Consistence — Power 
of  Imbibing  Water — Vacuoles  —  Physical  Activity — Naked 
Protoplasm— Protoplasm  Enclosed  in  Cell  Walls 1 

CHAPTER   II. 
THE  PLANT-CELL. 

General  Statement — Ectoplasm  and  Endoplasm — Bauds  and  Strings 
of  Protoplasm— Nucleus— Size  of  Cells— Forms  of  Cells— The 
Cell  the  Unit  in  Plants 15 

CHAPTER   III. 
THE  CELL-WALL. 

Composition — Growth  in  Surface — Growth  in  Thickness — The 
Markings  on  Cell  Walls— Theories  as  to  the  Mode  of  Thick- 
ening—Stratification  of  the  Cell  Wall— Formation  of  Chem- 
ically Different  Layers — The  Formation  of  Mucilage — Incom- 
bustible Substances  in  the  Wall 21 

CHAPTER   IV. 
THE  FORMATION  OF  NEW  CELLS. 

Cell-Formation  by  Division  :  (a)  Fission ;  (6)  Internal  Cell-Forma- 
tion— Cell-Formation  by  Union — Examples 36 


vni  CONTENTS. 

CHAPTER    V. 
THE  PRODUCTS  OF  THE  CELL. 

PAGE 

g  1.  Chlorophyll— §  2.  Starch,  Composition,  Form,  Molecular 
Structure — Grauulose  and  Starch-Cellulose  —  Formation  of 
Starch  Granules  in  the  Chlorophyll-Bodies — Formation  of 
Ordinary  Starch  Granules — §  3.  Aleurone  and  Crystalloids — 
£  4.  Crystals  in  Cells— §  5.  The  Cell  Sap— £  6.  Oils,  Resins, 
Gums,  Acids  and  Alkaloids fiu 

CHAPTER   VI. 
TISSUES. 

§  1.  The  Various  Aggregations  of  Cells  :  (a)  Single  Cells  ;  (b)  Fam- 
ilies ;  (c)  Fusions  ;  (d)  Tissues  ;  The  Cell- Wall  in  Tissues— 
§  2.  The  Principal  Tissues — Parenchyma — Collenchyma — 
Sclerenchyma — Fibrous  Tissue — Laticiferous  Tissue  —  Sieve 
Tissue— Tracheary  Tissue— §  3.  The  Primary  Meristem 63 

CHAPTER  VII. 
THE  TISSUE  SYSTEMS. 

§  1.  The  Differentiation  of  Tissues  into  Systems— §  2.  The  Epi- 
dermal System  of  Tissues — Epidermis — Trichomes — Stomata 
—  §  3.  The  Fibro- Vascular  System  of  Tissues  —  General 
Structure — The  Fibro- Vascular  Bundles  of  Pteris,  Polypodium, 
Adiautum,  Equisetum,  Selnginella,  Lycopodium,  Zea,  Acorus, 
Ricinus  and  Ranunculus — Of  Xylem  and  Phloem — Collateral, 
Concentric,  and  Radial  Bundles  —  Development  of  Fibro- 
Vascular  Bundles— §  4.  The  Fundamental  System— The  Tis- 
sues it  Contains— Cork— Lenticels 89 

CHAPTER  VIII. 
INTEHCKLLULAK  SPACES,  AND  SECRETION   RESERVOIRS 128 

CHAPTER  IX. 
THE  PLANT-BODY. 

§  1.  Generalized  Forms— Thallome— Caulome— Trichome— Root- 
Particular  Relations  of  Phyllome  to  Caulome— General  Modes 
of  Branching  of  Members— §  2.  Stems— The  Punctum  Vegeta- 
tionis— Buds— Adventitious  Stems— £  3.  Of  Leaves  in  General 
— §  4.  The  Arrangement  of  Leaves — £  5.  The  Internal  Struc- 
ture of  Leaves— §  6.  The  Roots  of  Plants,  Structure,  Root-Cap, 
Growth — Formation  of  New  Roots— Arrangement  of  Roots. .  .  133 


COXTKNTS.  IX 

CHAPTER    X. 
THE  CHEMICAL  CONSTITUENTS  OF  PLANTS. 

PAGE 

£  1.  The  Water  in  the  Plant— Amount  of  Water  in  Plants— Water 
in  the  Protoplasm — Water  in  the  Cell  Walla — Water  in  the 
Intercellular  Spaces — Equilibrium  of  the  Water  in  the  Plant — 
Disturbance  of  Equilibrium — Evaporation  of  Water — Amount 
of  Evaporation — The  Movement  of  the  Water  in  the  Plant 
— §  2.  As  to  Solutions— §  3.  Plan*.  Food— The  Most  Important 
Elements— The  Compounds  Used— How  the  Food  is  Obtained 
—How  Transported  in  the  Plant 166 

CHAPTER   XI. 
THE  CHEMICAL  PROCESSES  IN  THE  PLANT. 

§  1.  Assimilation— §  2.  Metastasis— Its  General  Nature— Trans- 
formation  of  Starch — Nutrition  of  Protoplasm — The  Storing  of 
Reserve  Material— The  Use  of  Reserve  Material— The  Nutri- 
tion of  Parasites  and  Saprophytes — The  Formation  of  Alkaloids 
—Results  of  Metastasis 178 

CHAPTER   XII. 
THE  RELATIONS  OF  PLANTS  TO  EXTERNAL  AGENTS. 

£  1.  Temperature — General  Relations — Absorption  of  Water  as  Af- 
fected by  Temperature — Evaporation — Assimilation — Metasta- 
sis— Death  from  too  Hijrh  a  Temperature — Death  from  too 
Low  a  Temperature — §  2.  Light :  General  Relations  of  Light 
to  Assimilation,  Light,  and  Metastasis — §  3.  Heliotropism— 
§  4.  Geotropism — §  5.  Certain  Movements  of  Plants  :  General 
Statement,  Spontaneous  Movements,  Movements  Dependent 
upon  External  Stimuli,  Movements  of  Nutation,  Movements 
of  Torsion...  ..184 


PART  II.    SPECIAL  ANATOMY  AND  PHYSIOLOGY. 


CHAPTER   XIII. 
CLASSIFICATION 

Principles  of  a  Natural  Classification — Critical — A  Comparison  of 
several  Systems 202 


x  CONTENTS. 

CHAPTER  XIV. 
THE  PKOTOPIIYTA. 

PAGE 

§  1.  Myxoinycetes— §  2.  Schizoinycetes— §  3.  Cyanophycea* 200 

CHAPTER  XV. 

THE  ZYGOSPORE^S. 

g  1.  Zoospome—  g  2.  Conjugate 220 

CHAPTER     XVI. 
THE  OOSPOKE,*:. 

§  1.  Volvox  and  its  Allies— §  2.  (Edogoniese—  §  3.  Cceloblasteae— 

§4.  Fucacese 243 

CHAPTER  XVII. 
THE  CARPOSPORE.K. 

§  1.  Coleochaete— §  2.  Florideae— §  3.  Ascomycetes— §  4.  Basidio- 
mycetes— §  5.  Characeae— §  6.  The  Classification  of  Thallo- 
phytes 270 

CHAPTER     XVIII. 

THE  BRYOPHYTA. 
§1.  Hepatic*— §2.  Musci 341 

CHAPTER  XIX. 

THE  PTERIDOPHYTA. 

p  1.  Equisetinse— §  2.   Filicinse — §  3.  Lycopodinse 361 

CHAPTER  XX. 
THE   PHANEROOAMIA. 

§  1.  General  Characters — §  2.  Gymnospernue — §  3.  Angriospermae 
— Glossology  of  Anjfiosperms — The  Tissues  of  Angiosperms — 
Classification  and  Economic  Botany  of  Monocotyledons — Class- 
ification and  Economic  Botany  of  Dicotyledons 389 

CHAPTER  XXI. 

CONCMTDING   OBSERVATIONS. 

The  Number  of  Species  of  Plants— The  Affinities  of  the  Groups  of 

Plants— The  Distribution  of  Plants  in  Time 566 


BOTANY. 


PART  I. 
GENERAL  ANATOMY  AND  PHYSIOLOGY. 


CHAPTER    I. 

PROTOPLASM. 

1.— If  We  examine  a  thin  slice  of  any  growing  part  of  a 
plant  (Fig.  1)  under  a  microscope  of  a  moderately  high 
power  (400  to  500  diameters),  there  may  be  seen  large  num- 
bers of  cavities  which  are  more  or  less  filled  with  an  almost 
transparent  semi-fluid  substance.  In  very  young  parts,  as 
in  buds  and  the  tips  of  roots,  this  substance  entirely  fills  the 
cavities,  and  makes  up  almost  the  whole  mass,  while  in  older 
parts  ifc  occurs  in  less  quantity,  and  usually  disappears  in 
quite  old  tissues.  This  substance  is  the  living  portion  of 
the  plant,  the  active,  vital  thing  which  gives  to  it  its  sensi- 
bility to  heat,  cold,  and  other  agents,  and  the  power  of  mov- 
ing, of  appropriating  food,  and  of  increasing  its  size  ;  it  is,  in 
fact,  that  which  is  sensitive,  which  moves,  appropriates  food, 
and  increases  in  size.  This  sensitive,  moving,  assimilating, 
and  growing  substance  is  named  PROTOPLASM.  * 

It  is  a  fact  of  great  biological  interest  that  in  animals  the  essential 
constituent  of  all  living  parts  is  a  substance  similar  to  the  protoplasm 
of  plants.  We  cannot  distinguish  the  two  by  any  chemical  or  physical 
tests,  and  can  only  say  that,  taken  as  a  whole,  the  protoplasm  of  plants 

*  So  named  by  its  discoverer,  Dr.  Hugo  Von  Mohl,  in  1846.  It  is  the 
Bioplasm  of  Dr.  Lionel  Beale  and  his  followers. 


BOTANY. 


differs  from  that  of  animals  in  its  secretions.  And  yet  these  secre- 
tions are  not  strictly  confined  to  plants  ;  cellulose,  starch,  chlorophyll, 
and  other  products  of  vegetable  protoplasm  formerly  regarded  as  pe- 
culiar to  plants  are  now  known  to  occur  in  undoubted  animals.  Botanists 
and  zoologists  have  labored  long  in  vain  to  discover  absolute  differences 
between  the  animal  and  the  vegetable  kingdoms;  between  the  higher 
plants  and  the  liiglier  animals  there  are  great  and  constant  differences  ; 
in  none  of  the  higher  animals,  for  ex- 
ample, is  chlorophyll  produced ;  but. 
in  the  lower  orders  of  both  kingdoms 
not  one  of  the  differences  observed  to 
hold  between  the  higher  plants  and 
--_  animals  exists. 

2.— The  exact  chemical  compo- 
sition of  protoplasm  has  not  hith- 
erto been  made  out,  but  it  is 
known  to  be  an  albuminous, 
watery  substance,  combined  with 
a  small  quantity  of  ash.  It  is 
probably  a  complex  mixture  of 
chemical  compounds,  and  not  a 
single  compound.  It  contains  at 
some  time  or  another  all  the  chem- 
ical constituents  of  plants.  Oil, 
granules  of  starch,  and  other  or- 
ganic substances  are  frequently 
present  in  it,  but  they  are  to  be  re- 
garded as  products  rather  than 
proper  constituents  of  pro!  oplasm. 


Fig.  1.— A  little  more  than  half  of 

i  longitudinal  section  of  the  apex  of 

yonng  root  of  the  Indian  corn. 


(a)  Water  makes  up  a  considerable 

Tlie  part  above  «  is  the  body  of  the  part  of  the  bulk  of  ordinary  protoplasm, 
root,  that  below  it  is  the  root-cap  ;  ,  .  ,  .  /  •  • 

r,  thick  outer  wall  of  the  epidermis;  and  is  much  more  abundant  in  its 
m  young  pith-cells;  /.young  wood-  active  than  in  its  dormant  conditions, 
cells  ;  g,  a  young  vessel ;  «,  t,  inner  T  , 

younper  part  of  root-cap  ;  a,  a,  out-    In    the  protoplasm   ot    fulif/o  tariai.s 

er^oldir  part  of  rootKjap.-After    (one  of  the  Siime  Moulds)  just  before 

the  formation  of  its  spores  there  is  70 

per  cent  of  water  ;  in  dry  seeds,  on  the  other  hand,  the  amount  is  not 
more  than  about  8  to  10  per  cent. 

(b)  As  to  its  molecular  constitution,  Strasburger  holds*  that  proto- 
plasm is  composed  of  minute  solid  particles  (not,  however,  of  a  crystal- 
line form),  separated  from  each  other  by  layers  of  water  (see  Cell-wall 

*  "  Studien  tiber  Protoplasma,"  1876. 


PROTOPLASM. 


paragraph  37,  and  Starch,  paragraph  69).  The  thicker  the  layers  of 
water  are,  the  more  watery  is  the  protoplasm,  and  vice  versa. 

(e)  Tests.  1.  If  a  protoplasmic  mass  is  moistened  with  a  solution  of 
iodine,  it  at  once  assumes  a  deep  yellow  or  brown  color. 

2.  If  treated  with  a  solution  of  copper  sulphate  and  afterward-*  with 
potash,  it  assumes  a  dark  violet  color. 


*   f 


Fig.  2.—  Parenchyma  cells  from  the  central  cortical  layer  of  the  root  of  FrUittati^ 
ii/tpenalis,  longitudinal  sections.  A,  very  young  cells  lying  closu  above  the  apex  of 
tlie  root,  still  without  cell  sap  or  vacuoles.  B,  cells  of  the  same  description  about 
i  wo  millimetres  above  the  apex  of  the  root  ;  by  the  entrance  of  cell  sap  the  vacuoles 
«,  s,  s  have  been  Conned.  G,  cells  of  the  same  description  about  seven  to  eight  mil- 
limetres above  the  apex  of  the  root.  In  all  the  figures,  A,  cell-wall  ;  p,  protoplasm  ; 
&,  nucleus  ;  kk,  nucleoli  ;  s,  vacuoles  ;  sey,  swelling  of  the  nucleus  under  the  influ- 
ence of  the  water  in  preparing  the  specimen.  X  500.  —  After  Sachs. 


8.  Treated  with  a  solution  of  sugar,  and  afterwards  with  sulphuric 
acid,  it  becomes  rose-red. 

4.  The  presence  of  protoplasm  may  be  demonstrated  in  a  tissue  by 
the  application  of  various  staining  fluids,  as  magenta,  carmine,  etc. 


BOTANY. 


5.  In  a  dilute  solution  of  potash  protoplasm  is  dissolved  ;  if,  how 
ever,  the  solution  is  concentrated,  tlie  form  of  the  protoplasm  remains 
unaltered  for  weeks,  but  upon  the  addition  of  water  it  at  once  dissolves. 

6.  Protoplasm  coagulates  upon  the  application  of  heat  (50  degrees 
Centigrade),  or  when  immersed  in  alcohol  or  dilute  mineral  acids. 

3. — In  consistence  protoplasm  is  a  soft-solid  substance, 
varying  from  an  almost  perfect  fluidity  on  the  one  hand  to 
a  considerable  degree  of  hardness  and  even  brittleness  on 
the  other.  This  difference  in  con- 
sistence is  mainly  due  to  the  vary- 
ing amounts  of  water  imbibed  by 
it,  hence  the  same  mass  may  at 
different  times  vary  greatly  in  this 
regard.  Generally  there  may  be 
seen  in  protoplasm  a  large  number 
of  minute  granules  enclosed  in  a 
transparent  medium  (Fig.  2,  A)  ; 
in  some  instances,  however,  the 
grannies  are  entirely  wanting,  or 
nearly  so.  By  the  withdrawal  of 
these  granules  for  a  little  distance 
from  the  surface  toward  the  cen- 
tre, a  mass  of  granular  protoplasm 

w,.  3.-oPticai  ^cTion  of  a  re-  <the  endoplasm)  may  appear  to  be 
trading  branch  of  a  large  piasmo-  surrounded  by  a  hyaline  envelope, 

diumof  Fuligo  variants  (.Ethalium      ,  i  •          .• 

fepticum  of  authors);  the  narrow    the     protoplasmic     SK111,    01'      CCtO- 

inner  granular  mass  of  protoplasm      ,  /.i        Tr       .      7  •   7  /      »  T»  • 

is  seen  to  be  surroimdod  by  a  broad   plasm  (the  Hdlttschicllt  of  PnngS- 

hyaline    portion,    the    ectoplasm,   i     •  j    rr         j    i  t    cu. 

which  in  this  case  is  radially  streak-   heim,  and  HaUptpldSmCl    Of    btras- 

fiu  burger)  (Fig.  3).     It  is  almost  al- 

d   by  a   hyalineen-    wavs   formed   when   protoplasm    is 

veiope.  X  aoo.-Aftcr  Hofmeister.  exposed  in  water  or  air  ;  but  it,  or 
something  very  much  like  it,  appears  to  be  generally 
present,  even  in  closed  cells. 

(a)  The  fine  granules  are  probably  not  proper  constituents  of  proto- 
plasm, but  finely  divided  assimilated  food-materials  immersed  in  the 
proper  protoplasm,  which  is  itself  colorless  and  transparent.  Proto- 
plasm destitute  of  granules  may  be  found  in  the  cotyledons  of  the 
bean  (PJiaseolus),  In  other  cases,  e.g.,  in  the  zygospores  of  Spirogyra, 
the  granular  and  coloring  matters  are  so  abundant  that  the  hyaline 
basis  can  no  longer  be  distinguished. 


PROTOPLASM.  5 

(6)  fctrasburger*  maintains  that  tlie  hyaline  envelope  is  not  simply  a 
portion  of  the  basis  or  ground  substance  of  the  protoplasm  deprived 
of  its  granules,  but  that  it  is  a  definite  modification  of  it,  and  endowed 
with  various  properties  quite  distinct  from  those  of  the  ground  sub- 
stance. 

4. — Active  protoplasm  possesses  the  power  of  imbibing 
water  into  its  substance,  and  as  a  consequence,  of  increasing 
its  mass.  This  power  varies  with  the  changes  in  external, 
and  also  in  internal  conditions  ;  many  seeds,  for  example, 
which  do  not  swell  up  (through  absorbing  water)  in  cold 
water,  will  do  so  when  placed  in  that  of  a  higher  tempera- 
ture ;  but  in  some  seeds  it  appears  that  imbibation  of  water 
will  not  take  place  until  after  a  period  of  rest. 

5. — When  the  amount  of  water  imbibed  is  so  great  that 
the  protoplasm  may  be  said  to  be  more  than  saturated  with 
it,  the  excess  is  separated  within  the  protoplasmic  mass  in 
the  form  of  rounded  drops,  termed  Vacuoles  (Vacuoli).  In 
closed  cells  these  may  become  so  large  and  abundant  as  to 
be  separated  only  by  thin  plates  of  the  protoplasm  (Fig.  2, 
B).  As  such  vacuoles  become  still  larger,  the  plates  are 
broken  through,  and  eventually  we  may  have  but  one  large 
vacuole  surrounded  by  a  thin  layer  of  protoplasm,  which 
lines  the  interior  of  the  cell  wall  (Fig  2,  C).  In  this  way 
some  masses  of  protoplasm  assume  a  bladder-like  or  vesicular 
form,  so  unlike  their  original  form  that  until -very  recently 
their  real  nature  has  not  been  understood.!  Frequently 
when  the  plates  which  separate  vacuoles  break  down,  instead 
of  breaking  entirely  away  they  become  pierced  with  several 
Urge  openings,  leaving  strings  or  bauds  of  protoplasm  which 
extend  across  the  cavity. 

Occasionally,  when  vacuoles  unite,  small  masses  of  the  protoplasm 
which  previously  separated  them  become  detached  as  free  rounded 

*  "  Studien  iiber  Protoplasma,"  1876.  See  also  Qr.  Jour.  Mic.  Science, 
1877,  p.  124  et  seq. 

f  Von  Mohl  gave  to  this  layer  the  name  Primordial  Utricle,  and  it  is 
still  frequently  used,  but  the  term  is  objectionable,  and  Sachs'  name  of 
Protoplasmic  Sac  is  to  be  preferred.  Treatment  with  glycerine,  strong 
alcohol,  or  any  other  substance  which  removes  the  water,  will  cause 
the  protoplasmic  sac  to  contract  and  become  visible. 


BOTANY. 


masses  iu  the  large  vacuole  ;  these  again  may  produce  vacuoles  within 
themselves,  and  thus  give  rise  to  a  peculiar  and  at  first  sight  perplex- 
ing structure  (Fig.  4). 

6.— The  most  remarkable  peculiarity  of  living  protoplasm  is 
its  physical  artirity.    When  the  proper  conditions  are  pres- 
a  living  mass  of  protoplasm  is  apparently  never  at  rest, 

but,  on  the  contrary, 
continually  altering  its 
shape  and  changing  the 
position  of  its  constit- 
uent parts.  The  move- 
ments are  all  of  the 
general  nature  ; 


same 

each  one  may  be  regard- 
ed as  the  aggregate  re- 
sult of  the  chemical  and 
physical  changes  taking 
place  in  the  substance 
of  the  protoplasm. 

We  may  study  the  ac- 
tivity    of     protoplasm 
under  two   conditions, 
which  will  give  us  the 
two  cases.      (1.)    The 
Activity  of  Naked  Pro- 
Fig.  4.-Forms  of  the  protoplasm  contained  in  toplasm,   and    (2. )   The 
cells.    A  and  B,  of  Indian  Com  (Zen  mai*) ;  A,    A    , .    • ,        *   T>    \      i 
cells  from  the  first  ieal-sh.-ath  of  a  germinatinsr  Activity  of   Protoplasm 
plant,  showing  the  frothy  condition  of  the  proto-  endoged  jn  fl  Cell-Wall. 


plasm,    the   many  vacuoles 

plates.      B,  cells  from  the  first  intcrnodf  of  the 


rated    by    thin 

7.—  The  Activity  of 

masses,  in'each  of  which  there  Naked      Protoplasm. 
is  a  vacuole,  b  ;  these  are  the  so-called  "  sap-vesi- 

cles."    6',  a  cell  from  the  tuber  of  the  Jerusalem  lllC        lOW        Organisms 

Artichoke  (.lli-limitlm*  /"i«?w>/*>  after  the  action  of  ,  ,. 

iodine  and  dilute  sulphuric  acid;  h,  cell-wall;  *,  kllOWll  as  the 
nucleuB^.contracteaprotopla.m.-After  Sachs. 


germinating  pi  mt ;  the  protoplasm  is  broken  up 
into  many  rounded  i 


present  the  best  examples  of  the  activity  of  naked  vegetable 
protoplasm.  In  their  plasmodia  (as  the  masses  of  naked  proto- 
plasm are  called),  many  kinds  of  movements  may  be  observed, 
the  commonest  of  which  is  streaming.  In  plasmodia  com- 
posed of  thin  (i.e.,  watery)  protoplasm,  streams  or  currents 
of  the  latter  may  be  seen  running  in  various  directions 


PROTOPLASM  MOVEMENTS.  7 

(Fig.  5).  The  streams  are  made  clearly  visible  by  the  motion 
of  the  granules  which  are  carried  along  by  the  moving  hya- 
line portion  of  the  protoplasm.  After  running  in  one 


Fig.  5. — A  email  mass  of  the  naked  protoplasm  (plasmodium)  of  Dldymium  «er 
K/a  ;  the  arrows  show  the  direction  of  the  currents,     x  30. — After  Hofmeister. 


direction  for  some  minutes  (about  five)  the  current  stops, 
and  then  it  usually  sets  in  an  exactly  opposite  direction  for 
about  the  same  length  of  time,  and  carries  back  the  previ- 
ously moved  protoplasm. 


The  formation  of  the  new  current  may  be  explained  as  follows  ; 
Let  A  ............  B  be  a  stream  in  which  the  movement  is  from  A 

to  B  ;  clearly  there  will  be  an  aggregation  of  protoplasm  about  B. 
When  the  current  in  the  direction  A  B  stops,  the  new  one,  in  the 
reverse  direction,  B  A,  begins  at  A,  by  the  movement  toward  it  of  the 
particles  nearest  to  it  ;  next  the  particles  further  off  move  toward  A  ; 
after  this,  those  still  further  off,  and  so  on.  The  current  extends  back- 
ward. So,  too,  when  a  stream  begins  de  novo,  it  is  propagated  back- 
ward from  the  point  of  beginning. 

8.—  Mass-Movement  (Amoeba-Movement).    In  the  flowing 

back  and  forth  in  the 
streams  the  movement 
may  be  greater  in  one 
direction  than  in  the 
other  ;  this  causes  a 
slow  motion  of  the 
whole  plasm  odium  in 
the  direction  of 
the  greatest  movement. 
When  this  takes  place 
in  the  case  of  streams 
which  begin  in  the  mar- 
gin of  the  plasmodium, 
protuberances  of  vari- 
ous shapes  arise  ;  these 
may  be  extended  into 
branches  (pseudopo- 
dia),  which  may  again 
be  branched  one  or 

times-        By    the 
r\t     flipon 

a       Complex 

moving  and  changing 
network  is  formed.  (See  Fig.  140,  page  208)  There  is  pos- 
sibly to  be  separated  from  the  above-described  mass-move- 
ment that  more  or  less  rapid  change  of  external  contour 
which  has,  from  its  resemblance  to  the  motions  of  the 
Amoeba,  been  denominated  the  Amoeba-movement  (Fig.  6). 
It  is  best  observed  in  the  so-culled  "Amoeba-form  "  stage  of 
*he  swarm-spores  of  the  Mvxomycetes. 


'gm  # 

Fig.6.-0ntlineof  a  plasmodium  of  ZHdymiwm   more 
nerpula  forming  pseudopodia.     The  heavy  black 


line  indicates    he  outline  at  the  beginnin    of  the 
observation  ;  the  psendopodium  a-b  formed  in  8   branches 


*.  c-d  in  30,  and  c-e  in  55  seconds, 

—After  Hofmcister. 


PROTOPLASM  MOVEMENTS.  9 

While  in  thinner  protoplasm  the  streaming  and  mass- 
movements  are  always  horizontal,  or,  at  least,  parallel  witli 
the  surface  upon  which  the  plasmodium  rests,  in  the  case  of 
tougher  protoplasm  they  may  give  rise  to  branches  which 
have  an  upward  direction,  as  in  the  formation  of  sporangia. 

9.— Effect  of  External  Influences.  The  movements  of 
the  protoplasm  of  the  Myxomycetes,  and  probably  to  a 
greater  or  less  extent  of  all  plants,  are  suspended  by  certain 
external  influences.  Violent  jarring,  pressure,  a  thrust  as 
with  the  point  of  a  pin  or  pencil,  electrical  discharges, 
sudden  changes  of  the  temperature,  and  sudden  changes  in 
the  concentration  of  the  surrounding  fluid,  stop  the  move- 
ments, and  cause  the  plasmodium  to  contract  into  one  or 
more  spheroidal  masses.  When  these  influences  cease,  if 
they  have  not  been  so  violent  as  to  destroy  the  organization 
of  the  protoplasm,  it  returns  after  a  greater  or  less  length 
of  time  to  its  original  form,  and  the  movements  are  resumed. 

(a)  The   effect   of  mechanical   disturbances  (jarring,  pressure,  and 
thrust)  may  be  best  studied  in  the  tougher  or  least  fluid  plasmodia 
(e.g. ,  of  Stemonitis  fusca). 

(b)  The  effect  of  electrical  discharges  may  be  studied  by  placing  a 
small  plasmodium  (e.g.,  Didymium  serpula)  upon  a  glass  plate  provided 
with  platinum  points  which  are  in  connection  with  the  poles  of  an 
induction  apparatus.    When  a  discharge  takes  place  through  a  narrow 
branch  (pseudopodium)  it  contracts  so  violently  as  to  be  broken  up  into 
a  row  of  little  spheres  ;  if  it  takes  place  through  the  mass  of  the  plas- 
modium it  becomes  more  or  less  spherical  by  its  contraction.  ,In  any 
case,  if  the  shock  has  not  been  too  severe,  the  protoplasm  after  a  while 
returns  to  its  normal  shape  again.* 

(c)  The  plasmodium  of  Didymium  serpula,  when  removed  from  a  tem- 

*  Kuhne  performed  the  following  curious  experiment.  Taking  a 
portion  of  the  plasmodium  of  Didymium  serpuln.,  in  its  resting  state, 
he  mixed  it  with  water  so  as  to  make  a  pulpy  or  pasty  mass.  With 
this  he  filled  a  piece  of  the  intestine  of  a  water-beetle,  and  tying  the 
ends,  laid  it  across  the  electrodes  of  an  induction  apparatus.  The  pre- 
paration was  kept  in  a  film  of  water  in  a  damp  chamber  for  twenty-four 
hours,  at  the  end  of  which  time  it  was  considerably  distended.  He  now 
allowed  the  electrical  current  to  pass  through  it,  when  it  contracted 
itself  "like  a  colossal  muscle-fibre."  Upon  extending  it  by  pulling  at 
the  ends,  and  then  sending  through  it  a  stronger  electrical  current,  it 
toiitractt'd  itself  v.ue  third  of  its  length. 


10  BOTANY. 

perature  of  20°  C.  to  one  of  30°  C.  (68°  to  86°  Fahr.);  withdraws  its  pseud- 
opodia  and  ceases  its  activity  iu  the  space  of  five  minutes.  In  au  hour 
alter  the  restoration  of  the  normal  temperature  (20°  C.)  the  movements 
begin  again.  If  the  temperature  is  raised  to  35°  C.  (95°  Fahr.)  the 
organization  of  the  plasmodiuni  is  destroyed. 

The  plasmodium  of  Ftdigo  variaiis,  Sommf.  (^tltalinm  septicum, 
Fr.),  when  placed  in  a  chamber  surrounded  by  ice,  contracts  into  a 
rounded  form  and  ceases  all  motion  ;  upon  gradually  raising  the  tem- 
perature again  the  normal  state  is  resumed. 

(d)  In  glycerine,  a  concentrated  solution  of  sugar,  a  five  per  cent  solu- 
tion of  potassium  nitrate,  or  a  five  per  cent  solution  of  sodium  chloride,  a 
plasmodium  contracts,  and  becomes  rounded  and  motionless.  A  suddi-u 
decrease  in  the  concentration  of  the  solution  by  which  a  plasmodiuni 
is  surrounded  also  results  in  a  stoppage  of  its  movements.  A  plasmo- 
dium of  Didymium  serpula,  when  placed  in  a  one  per  cent  solution 
of  potassium  nitrate,  and  allowed  time  to  regain  its  activity,  suddenly 
rounds  itself  up  and  stops  its  movements  when  the  preparation  is 
washed  out  with  distilled  water  ;  after  the  lapse  of  a  few  minutes  (ten 
to  twelve)  the  activity  begins  to  show  itself  again,  and  in  half  an  hour 
the  normal  state  is  restored. 

10.— Ciliary  Movement.  The  swimming  of  swarm-spores, 
spermatozoids,  and  many  other  naked  protoplasmic  bodies,  is 
due  to  the  rapid  vibratory  motion  of  extremely  small  whip- 
like  extensions  of  the  hyaline  portion  of  the  protoplasm. 

Examples  of  ciliary  movement  are  very  common.  In  some  swarm- 
spores,  as  in  those  of  Vaucheria,  the  whole  surface  is  covered  with  short 
cilia  ;  in  others,  as  in  (Edogonium,  the  cilia  form  a  crown  al.out  the  hya- 
line anterior  extremity  ;  those  of  Pandorina  and  Cladophora,  and  the 
spermatozoids  of  Bryophytes  and  Pteridophytes,  have  two  or  more  cilia  ; 
while  the  swarm-spores  of  Myx<>mycetes  have  but  one. 

The  rapidity  of  tli e  swimming  motion  produced  by  cilia  is  consider- 
able, as  shown  by  measurements  made  by  Hoi'meister*  in  the  case  of 
swarm-spores,  viz.  : 
Fttliyo  varians  (^ffithalium  septicum). ..        .7  to  .9  mm.  per  second. 

Lycogola  epidetidrum .33mm.   " 

(Edogonium  tesicatum 15  to  .20  mm.  "        " 

Vancheria  sp 10  to  .14  mm.  "         " 

1 1  .—The  Activity  of  Protoplasm  Enclosed  in  a  Cell- wall. 
The  movements  of  protoplasm  in  closed  cells  differ  but 
little  from  those  in  naked  ones  ;  the  differences  are  sucli  as 
are  due  to  the  fact  that  in  the  latter  case  the  protoplasm  is 

*  "  Lehre  von  der  Pflanzenzelle,"  p.  30. 


PROTOPLASM  MOVEMENTS.  11 

free  to  move  in  any  direction,  while  in  the  former  its  move- 
ments are  greatly  restricted  by  the  surrounding  walls.  In 
closed  cells  there  are  two  general  kinds  of  movements — one 
a  streaming,  the  other  a  mass  movement — comparable  to  the 
streaming  and  Amoeba  movements  of  the  naked  cells  or  pro- 
toplasmic masses.  No  movement  takes  place,  however  (at  any 
rate  to  no  great  extent),  until  the  vacuoles  are  quite  large. 

12 — The  streaming  movements  occur  in  the  protoplasmic 
strings,  bands,  and  plates  which  cross  or  separate  the  vacu- 
oles, and  in  the  lining  layer  of  protoplasm  which  invests  the 
inner  surface  of  the  cell-wall.  The  motion,  in  many  cases, 
shows  the  same  alternation  as  in  the  Myxomycetes,  the  direc- 
tion of  the  streaming  usually  being  reversed  after  the  lapse 
of  a  few  minutes. 

The  mass-movement  in  closed  cells  is  not  as  clearly  sepa- 
rated from  the  streaming  as  in  naked  cells.  It  usually  con- 
sists in  a  sliding  or  gliding  of  the  protoplasm  upon  the  inner 
surface  of  the  cell-wall,  in  much  the  same  way  as  the  naked 
plasmodium  of  one  of  the  Myxomycetes  moves  upon  the  sur- 
face of  its  support.  The  limited  space  in  which  its  move- 
ment must  take  place  in  closed  cells,  and  its  disposition  over 
the  whole  inner  surface  of  the  wall,  compel  the  protoplasm 
to  move  in  opposite  directions  upon  opposite  sides  of  the 
cell.  There  is  thus  a  kind  of  rotation  of  the  protoplasm 
when  the  movement  of  all  its  parts  is  uniform. 

(a)  The  streaming  movements  may  be  studied  in  the  stamen-hairs  of 
Tradescantia  Virginica,  the  stinging  hairs  of  the  nettle  (Urtica),  the 
hairs  of  Cucurbita,  Ecbalium,  and  Solatium  tuberosum,  the  styles  of 
Campanula,  the  easily  separated  cells  of  the  ripe  fruit  of  Symphoricar- 
pus  racemosus,  the  young  pollen  grains  of  (Enothera,  and  the  paren- 
chyma of  succulent  monocotyledons — e.g.,  in  the  flower  peduncles  and 
the  filaments  of  Tradescantia.     The  parenchyma  cells  of  the  leaves  of 
many  trees  and  of  the  prothallia  of  ferns  and  Equisetums  show  a  net- 
work of  hyaline  strings  in  which  a  streaming  may  with  difficulty  be  seen. 

Among  the  lower  plants  good  examples  may  be  found  in  the  hyphae 
of  some  Saprolegniae,  and  in  the  cells  of  Spirogyra,  Closlerium,  Denti- 
cetta,  and  Coscinodiscus. 

(b)  In   many  capes  (e.g.,  in  the   unfertilized    embryo  sac  of   many 
Phanerogams,  in  the  young  endosperm  cells,  and  in  the  spore-mother- 
cells  of  Anthoceroslwvis) — where  the  strings  and  bands  resemble  those 
in  the  cases  cited  above — no  movement  of  the  protoplasm  is  visible, 


12  BOTANY. 

doubtless  because  of  the  mechanical  injury  of  the  cells  in  making  the 
preparation,  and  the  disturbing  influence  of  the  water  in  which  it  is 
mounted. 

(c)  lu  the  stamen-hairs  of  Tradeseanlia    Virgin-tea  the  protoplasm 


Fig.  7.  —An  optical  section  of  a  cell  of  one  of  the  stamen-hairs  of  Tradefcantia 
finjMtUe,  after  treatment  with  a  solution  of  sugar.  The  protoplasmic  sac  has 
partly  collapsed,  on  account  of  the  withdrawal  of  some  of  the  interior  water  by  the 
sugar  solution.  At  the  bottom  of  the  cell  is  the  lame  nucleus  ;  in  the  strings  and 
bands  of  protoplasm  there  are  streamings  of  the  protoplasm,  shown  by  the  arrows. — 
After  Hofmeister. 

forms  a  rather  thick  layer  over  the  inner  surface  of  the  cell-wall,  and 
in  some  part  of  this  layer  the  nucleus  lies  imbedded.  From  the  nucleus 
and  from  various  parts  of  the  protoplasmic  layer  there  pass  to  the 
opposite  side  of  the  cell  thicker  or  thinner  bands  and  strings,  always 


PROTOPLASM  MOVEMENTS.  13 

however,  more  or  less  parallel  with  the  longer  axis  of  the  cell  (Fig.  7). 
In  a  string  there  may  toe  one,  two,  or  three  currents  ;  when  there  are 
two  they  are  in  opposite  directions  ;  when  there  are  three  the  central 
one  takes  one  direction  and  the  two  outer  ones  the  other. 

The  strings  are  not  stationary  in  the  cell,  but,  on  the  contrary,  they 
change  their  position  with  a  considerable  rapidity,  and  in  a  prepara- 
tion soon  pass  out  of  the  focus  of  the  microscope.*  By  this  change  of 
place  two  strings  may  come  together  and  fuse  into  one,  or  a  string  may 
pass  to  the  side  of  the  cell  and  become  obliterated  by  fusing  with  the 
protoplasmic  sac.  New  strings  may  be  formed  by  a  process  exactly 
opposite  to  the  one  just  described.  A  stream  in  the  substance  of  the 
lining  protoplasm  forms  a  ridge  projecting  into  the  vacuole  ;  this  ridge 
gradually  becomes  higher,  and  finally  breaks  away  from  the  protoplas- 
mic sac,  retaining  its  connection  only  at  the  ends.  After  a  stream  has 
been  running  in  a  certain  direction  for  from  ten  to  fifteen  minutes,  the 
motion  suddenly  becomes  slower  and  soon  stops  entirely  for  from  a  few 
seconds  to  several  minutes,  and  then  begins  to  move  in  the  opposite 
direction.  The  new  movement  begins  and  spreads  as  in  the  Myxomy- 
cetes  (see  paragraph  7). 

(d)  In  the  hairs  of  Cucurbita  Pepo  the  arrangement  of  the  protoplasm 
is  much  as  in   Tradescantia.     The  strings  and  bands  are,  however, 
broader,  and  frequently  contain    several   currents,  and   the   nucleus, 
instead  of  being   imbedded  in  the  lining  layer  of   protoplasm,  is  in 
a  centrajly  placed  mass.     There  is  a  more  rapid  change  in  the  form 
and  position  of  the  bands  and  strings  than  in  Tradescantia,  but  the 
streaming  motion  is,  on  the  contrary,  considerably  slower.    The  reversal 
of  the  streaming  currents  takes  place  in  from  seven  to  twenty  minutes. 

(e)  In  most  cases  the  streams  lie  in  the  lining  protoplasmic  layer  of 
the  cell,  or  form  low  ridges  upon  its  inner  surface.     This  is  the  case 
in  the  hairs  of  the  style  of  Campanula,  in  hyphse  (of  fungi),  and  in  the 
suspensor  and  young  embryo  of  Funkia  cterulea.     In  long  cells,  the 
movement  being  parallel  with  the  longer  axis,  there  may  be,  as  in  the 
pollen  tube  of  Zostera  marina,  currents  passing  up  one  side  and  down 
the  other.f 

*  This  fact  must  be  borne  in  mind  in  studying  the  movements  of  pro- 
toplasm in  these  cells,  otherwise  grave  mistakes  may  be  made.  Ono 
string  may  move  out  of  focus,  and  another,  with  a  contrary  current, 
may  move  into  it,  and  thus  a  reversal  of  the  current  in  the  first  string 
may  erroneously  be  supposed  to  have  taken  place. 

f  To  study  the  movements  of  protoplasm  in  pollen  tubes  it  is  usual  y 
necessary  only  to  make  a  thin  longitudinal  slice  of  the  stigimt,  and  to 
mount  and  cover  it  in  the  usual  way,  using  no  water,  however.  After 
placing  it  under  the  microscope  the  preparation  should  be  carefully 
crushed,  when  some  of  the  pollen  tubes  may  be  distinctly  seen.  Their 
movements  frequently  continue  for  some  hours  in  such  prepnrations 


14  nor  ANY. 

(/)  The  passage  from  the  condition  in  the  last  examples  (the  so- 
called  circulation  of  protoplasm)  is  an  easy  one  to  the  cases  where  the 
whole  mass  of  protoplasm  moves  along  the  cell-wall  as  a  broad  stream, 
passing  up  one  side  and  down  the  other  (the  so-called  rotation  of  pro- 
toplasm). Common  and  well-known  examples  of  this  kind  of  mass-move- 
ment occur  in  Cham,  Naias,  and  Vallisneria.  It  may  also  (on  the 
authority  of  Meyen)  be  studied  in  the  root-hairs  of  many  land  plants — 
e.g.,  of  Impatiens  Balmmiiia,  Vitia  falm,  Ipoma'a  purpuren,  <  ucumis, 
Cucurbita,  Ranunculus  sceleratus,  and  Marchantia  polymorpha. 


CHAPTER    II. 

THE    PLANT-CELL. 

13. — In  some  cases  plant  protoplasm  has  no  definite  or 
constant  form.  This  is  its  permanent  condition  in  some  of 
the  lowest  plants — e.g.,  the  Myxomycetes.  In  most  other 
lower  plants,  and  in  all  the  higher  ones,  it  has  this  condition 
only  temporarily,  if  at  all.  In  the  great  majority  of  cases, 
however,  the  protoplasm  of  which  a  plant  is  composed  has  a 
definite,  and,  within  certain  limits,  a  constant  form.  It  usu- 
ally appears  in  more  or  less  rounded  or  cubical  masses  of 
minute  size,  and  which  may  or  may  not  be  surrounded  by  a 
cell-wall.  In  this  condition  it  constitutes  the  Plant-Cell. 

The  undifferentiated  protoplasm  of  the  Myxomycetos  reminds  us  of 
the  lower  Monera  among  animals.  In  Bathybius  and  Protamoaba  the 
naked  protoplasm  of  which  they  are  composed  has  no  constant  form. 
In  Protoinyxa  we  have  a  few  simple  transformations  which  are  in  every 
respect  comparable  to  those  of  the  Myxomycetes.*  In  higher  animals 
the  protoplasm  exists  in  minute  and  definitely  marked  masses,  termed 
cells,  or  corpuscles,  and  these  have  been  shown  to  be  the  exact  horno- 
lojjues  of  the  cells  of  plants. 

14. — While  in  young  cells  provided  with  a  wall  the  pro- 
toplasm fills  the  whole  cavity,  as  in  A,  >ig.  2  (p.  3),  in 
older  ones  it  never  does  so,  and  generally  these  contain  only 
a  very  small  portion  of  it,  as  a  thin  layer  covering  the  inner 
surface  of  the  cell-wall  (B  and  C,  Fig.  2).  Close  examina- 
tion shows  that  this  protoplasmic  sac  consists  of  (1)  a  firmer 
hyaline  layer,  the  ectoplasm,  which  is  in  contact  with  the 

*  See  further  on  this  subject  in  paragraph  222,  Chapter  XI.  For  a 
short  account  of  these  interesting  animal  forms  mentioned  above,  the 
student,  is  referred  to  Dr.  Packard's  "  Zoology  for  Students  and  Gen- 
eral Readers,"  (p.  18  et  seq.)  in  the  series  of  which  the  present  work 
forms  a  part,  and  his  "  Life-Histories  of  Animals,"  where  are  also  given 
numerous  references  to  fuller  accounts. 


16  BOTANY. 

^cell-Avail ;  and  (2)  within  this  a  less  dense  granular  one,  the 
endoplasm  ;  the  two  layers  are,  however,  not  separated  from 
each  other  by  any  sharp  line  of  demarkation.* 

When  the  endoplasm  attains  a  considerable  thickness  it  Incomes  dif- 
ferentiated into  an  external  denser  layer  and  an  internal  less  dense 
one.  Often  one  of  these  layers  may  be  found  to  be  in  motion  while  the 
other  is  at  rest.f 

15. — There  may  almost  always  be  seen  in  plant-cells  bands 
'.or  strings  of  protoplasm  which  lie  in  or  between  the  vacu- 
.oles  (Fig.  2,  B).  They  are  at  first  thickish  plates  which 
separate  vacuoles,  but  afterward  they  become  narrower  as 
the  vacuoles  enlarge,  and  at  last  they  disappear  entirely.  In 
these  bands  and  strings,  as  previously  stated  (paragraph  12), 
streaming  movements  are  frequently  to  be  seen. 

16. — Each  of  the  protoplasm  masses  constituting  the  cells 
of  most  plants  usually  has  a  portion  of  its  interior  substance 
differentiated  into  a  firmer  rounded  body,  the  nucleus  Its 
normal  position  is  in  the  centre  of  the  cell ;  but  it  may  be 
displaced  and  pushed  aside  by  the  vacuoles,  so  that  in  an 
optical  section  of  the  cell  it  may  often  appear  to  be  in  the 
margin.  The  nucleus  is  to  be  regarded  simply  as  a  modified 
part  of  the  protoplasm  of  the  cell,  and  not  as  something  dis- 
tinct from  it.  It  may  dissolve,  and  its  substance  pass  into 
that  of  the  remainder  of  the  cell ;  afterward  a  nucleus  may 
form  again  ;  and  this  may  occur  a  number  of  times.  Com- 
monly in  each  nucleus  one  or  more  small  rounded  granules 
may  be  seen ;  these  are  called  the  nudeolL  The  nucleus 
.  may  form  a  skin  (hautschicht)  about  itself,  and  vacuoli  may 
be  present  in  its  interior. 

17. — Cells  are  of  very  varying  sizes.  They  differ  in  dif- 
ferent plants,  and  also  in  the  different  parts  of  the  same 
plant.  In  but  few  cases,  however,  are  they  of  great  size,  by 
far  the  larger  number  being  microscopic.  The  most  striking 


*  These  two  layers  were  first  described  by  Pringsheim  in  his  "  Theorio 
der  Pflanzenzelle,"  1854. 

f  Cf.  Strasburger,  "  Studien  uber  Protoplasms,"  1876  ;  and  Qr.  Jr. 
Me.  Science,  1877,  pp.  124-132. 


THE  PLANT-CELL. 


examples  of  large  cells  are  found  in  the  Thallophytes  ;  Nitella, 
for  example,  has  cells  50  mm.  (2  inches)  long,  and  1  mm. 
(.04  inch)  thick.  According  to  Von  Mohl,  the  bast-cells 
of  a  species  of  palm  (Astrocaryum)  are  from  3.6  to  5.6  mm. 
(.13  to  .21  inch)  in  length.  For  ordinary  plants  the  average 
size  of  the  cells  may  be  given  as  from  .1  to  .02  mm.  (.004  to 
.0008  inch).  From  this  average  size  the  dimensions  of  cells 
decrease  to  exceedingly  small  magnitudes.  In  the  Yeast 
Plant  (Saccharomyces  cerevisice)  the  cells  are  about  .008  mm. 
(.0003  inch)  in  diameter.  The  cells  of  Bacterium  termo  are 
from  .0021  to  .0028  mm.  long  and  from  .0028  to  .0005  mm. 
broad  (.0001-.  00008  by  .00008-. 00002  inch). 

The  following  table,  taken  from  Hofmeister's  "  Lelire  von  der  Pflan- 
zenzelle,"  is  useful  as  showing  how  the  dimensions  of  similar  cells 
vary  in  different  plants  : 

TABLE  OF  DIMENSIONS  OF  VARIOUS  KINDS  OF  CELLS  OF  WOODY 
PLANTS. 

(In  decimals  of  a  millimetre.) 


£! 

L, 

M 

g 

jj 

si 

gs 

>i 

t>     •§ 

3 

2S 

g  ^ 
•S-" 

2«  . 

i**3 

I|| 

*L 

o«« 

gt. 

P 

fe^ 

L)  S*w 

II! 
s*- 

jli 

5  2.i; 
I65 

III 

Cambium-cells,  average  length  
Vessel-like  wood-cells,  average  length  

.201 
.308 

.413 

.528 

.339 
1.179 

.786 

1.511 
2.020 

Bast-like  wood-cells,  average  length  

.301 

.533 

.712 

1.819 

Vescel  -cells  of  the  wood,  average  length  
Latticed  cells  of  young  secondary  bark,  aver- 

.205 
212 

.404 
520 

.615 

BaJt-cells  of  young  secondary  bark,  average 

798 

1  W> 

403 

1  152 

2.183 

Cells'of  medullary  ray  in  the  cambium  ring, 

maximum  length  in  tangential  section  
Do.  do  ,  maximum  width  in  tangential  sec- 

.321 

.437 

.178 

.838 

.466 

.049 

tion        

.041 

.076 

.011 

.017 

.056 

.014 

Cells  of  medullary  ray  in  the  young  wood, 
average  length  in  tangential  section  
Do.,  do.,  average  width  in  tangential  section. 

.376 
043 

.519 
.077 

.285 
.019 

.567 
.037 

.630 
.075 

.095 
.019 

Cells  of  medullary  ray  in  the  young  secon- 
dary bark,  average  length    in   tangential 
section      

.342 

.912 

.468 

504 

744 

m 

Do.,  do.,  average  width  in  tangential  sec- 
tion   

.057 

.066 

.031 

.076 

.075 

.026 

18  BOTANY. 

18. — Every  free  mass  of  protoplasm  tends  to  assume  a 
spherical  form.  The  free  cells  of  the  unicellular  water  plants 
are  generally  more  or  less  rounded,  as  are  also  the  floating 
spores  of  most  aquatic  Thallophytes.  In  plants  composed  of 
masses  of  cells  their  mutual  pressure  gives  them  an  angular 
outline.  AVhere  the  pressure  is  slight  the  cells  depart  but 
little  from  the  spherical  shape,  but  as  it  becomes  greater 
they  assume  more  and  more  the  form  of  bodies  bounded  by 
planes.  If  the  diameters  of  the  individual  cells  are  equal 
and  the  development  of  the  mass  of  cells  has  been  uniform 
in  every  direction,  we  may  have  regular  cubes,  or  twelve-sided 
bodies,  i.e.,  dodecahedra.  It  is  rarely  the  case,  however, 
that  the  cells  have  a  perfectly  regular  form.  Even  when 
their  diameters  are  approximately  equal,  they  are  generally 
so  much  distorted  that  they  are  best  described  as  irregular 
polyhedra. 

19. — It  much  more  frequently  happens  that  cells  grow 
more  in  some  directions  than  in  others,  and  thus  give  rise 
to  elongated  and  many  irregular  forms.  In  many  of  the 
Thallophytes  the  long  filaments  composing  the  plants 
are  made  up  of  elongated  cylindrical  cells  placed  end  to 
end  ;  while  in  others  the  cells  are  repeatedly  and  irregularly 
branched. 

In  higher  plants  many  elongated  cells  occur,  but  here, 
by  pressure,  they  generally  become  prismatic  in  cross-section. 

(a)  Many  forms  of  cells  Lave  been  enumerated,  but  they  may  all  be 
arranged  under  the  two  principal  kinds    indicated  above,   viz.,    the 
short,  and  the  elongated.     As  will  be  more  fully  shown  hereafter,  the 
various  kinds  of  short  cells  constitute   what  is  called  Parenchyma; 
hence  the  cells  themselves  are  termed  Parenchymatous  cells,  or  Paren- 
chyma cells.     Similurly,  certain  kinds  of  the  elongated  cells  constitute 
Prosenchyma,  and  hence  such  are  termed  Prosenchyniatous  cell?,  or 
Pn  senchyma  cells.     While  it  is  impossible  to  draw  an  exact  line  be- 
tween parenchymatous  and  prosenchymatous  forms,  yet  the  terms  are 
valuable,  and  are  in  constant  use  to  indicate  the  general  form. 

(b)  Duchartre*  has    made  an    excellent    classification   of  the  prin- 

*  In  his  Elements  de  Botanique,"  second  edition,  a  large  and 
valuable  work,  which  the  student  may  profitably  consult. 


THE  PLANT-CELL. 


cipal  forms  of  cells,   which  is   given   below   in   a   slightly   modified 
form: 


Cell  globular  or 
ovoid,  in  section 
round  or  oval  ....  Spheroidal. 

Cell  polyhedral.  Polyhedral. 

Cell  a  parallelo- 
pipedon,  in  section 
rectangular CubmdcU. 

Cell  tabular, 
with  an  elongated 
rectangular  s  e  c  - 
tion Tabular. 


Cell  short 

(Parenchyma-- 

tow). 


Outline  smooth, 
or  without  promi- 


With  prominences. 


f  Cell  ramose, 
having  short  and 
irregular  projec- 
tions   Ramose. 

Cell  star-shap- 
ed, having  long 
projections  which 
are  more  regular. .  Stellate. 


Cell  elongated. 


Cell  cylindrical,  with  its  ends  at 
right  angles  to  its  axis,  or  but  little 
inclined Cylindrical. 

Cell  prismatic,  with  its  ends  at 
right  angles  to  its  axis,  or  but  little 
inclined Prismatic. 

Cell  fusiform  [cylindrical  or  pris- 
matic], with  its  ends  oblique  and 

pointed Fusiform 

(Prosenchymcir- 
tous). 


20. — When  one  or  more  sides  of  a  cell  are  not  in  contact 
with  other  cells,  as  is  the  case  with  those  cells  which  com- 
pose the  surface  of  plants,  the  free  sides  are  generally  con- 
vex, and  they  often  become  more  or  less  prolonged,  sometimes 
in  a  curious  way.  The  velvety  appearance  of  the  petals  of 
many  plants  is  due  to  such  prolongations  of  the  free  sides  of 
the  surface  cells  (Fig.  8).  Of  a  somewhat  similar  nature  are 
the  tubular  extensions  of  the  surface  cells  of  young  roots — 
the  root-hairs.  And  here  we  may  also  place  the  curious  star- 
shaped  cells  which  project  into  the  intercellular  spaces  in  the 
interior  of  the  stem  of  the  water  lily  (Fig.  9),  and  those 
which  compose  the  pith  of  certain  rushes  (Fig.  9i). 

21.— In  the 'unicellular  plants  each  cell  is  an  independent 


BOTANY. 


organism  ;  it  absorbs  nourishment,  assimilates,  grows,  and 
reproduces  its  kind.  In  the  higher  plants,  although  this 
independence  is  not  so  evident,  it  still 
exists  in  a  considerable  degree.  Here 
each  cell  is  an  individual  in  a  commu- 
nity ;  but  it  still  has  a  life-history  of  its 
own,  a  formation  (genesis),  growth,  ma- 
turity, and  death.  It  is  the  unit  in  the 
plant.  Upon  its  changes  in  size,  form, 
and  structure  depend  the  volume,  shape, 
etai  and  structural  characters  of  the  plant 


thefree"(upper)  sides  of  the  logical   Unit  of   the  plant. 

cells.    Mag.  —  After    Du-  A       ,  ,  ,     ,  „     .  , 

ehartre.  22.  —  As  the   whole  structure  of   the 

plant  is  an  aggregation  of  cells,  so   the  functions  of  the 
whole,  or  of  any  part  of  a  plant  are  but  the  sum  or  result- 


Pie.  9. 

Fit;.  0. — A  cross-section  through  the  petiole  of  Nuphar  advena  ;  s,  «,  star-shaped 
cells  projecting  into  the  intercellular  spaces  i,  i  ;  g.  a  reduced  fibro-vascular  bundle. 
Magnified.— After  Sachs. 

Fig.  96. —  Stellate  cells  from  the  pith  of  Jiincun  e/uKus,  magnified.—  After  Du- 
chartre. 

ant  of  the  physiological  activities  of  its  individual  cells. 
The  cell  is  thus  also  the  Physiological  Unit  of  the  plant. 


CHAPTER    III. 

THE   CELL-WALL. 

23.— In  all  but  the  lowest  plants  the  protoplasm  of  every 
cell  surrounds  itself  sooner  or  later  with  a  covering  or  wall 
of  cellulose.  The  substance  of  the  cell-wall  is  a  secretion 
from  the  protoplasm.  Cellulose,  as  such,  does  not  exist  in 
the  protoplasm  ;  it  is  formed  on  the  surface  when  the  wall  is 
made.  On  its  first  appearance  the  Avail  is  an  extremely  thin 
membrane,  but  by  subsequent  additions  it  may  acquire  vary- 
ing degrees  of  thickness.  The  cell-wall  forms  a  complete 
covering  for  the  protoplasm  ;  there  are  at  first  no  openings 
in  it,  at.  least  none  that  are  visible  ;  later  in  the  life  of  the 
cell  pores  are  formed  in  the  wall  in  some  cases,  while  quite 
frequently  in  dead  cell-walls  there  are  large  perforations  of 
various  sizes  and  shapes. 

(a)  Cellulose  is  related  chemically  to  starch  and  sugar.  Its  composi- 
tion is  C12  H20  OIQ.  It  is  tough  and  elastic.  It  is  but  slightly  soluble 
in  dilute  acids  and  alkalies,  and  not  at  all  in  water  and  alcohol.  In 
water,  however,  it  swells  up  from  imbibing  some  of  the  liquid,  but  it 
shrinks  again  in  bulk  when  dried. 

(6)  Tests.— 1.  If  cellulose  is  treated  with  dilute  sulphuric  acid,  and 
shortly  afterward  with  a  weak  solution  of  iodine,  it  is  colored  blue. 

2.  Treated  with  Schult/'s  Solution  it  assumes  a  blue  color. 

(c)  In  the  Myxomycetes,  if  the  large  mass  of  protoplasm  composing  a 
plant  is  somewhat  dried,  it  separates  itself  into  smaller  masses,  which 
surround  themselves  with  a  cell-wall.  Upon  applying  sulphuric  acid 
and  iodine,  the  characteristic  blue  color  of  cellulose  appears,  showing 
that  the  wall  is  a  true  wall  of  cellulose.  If,  however,  any  such  dried 
mass  of  protoplasm  is  subjected  to  the  proper  conditions  of  moisture 
and  temperature,  the  cell-wall  is  dissolved  and  absorbed  into  the  proto- 
plasmic mass.  Tests  applied  now  utterly  fail  to  show  the  presence  of 
cellulose.  These  observations  prove  the  truth  of  the  statement  that 
cellulose  is  a  secretion,  and  that  it  is  not  contained,  <is  cellulose,  in  the 
protoplasm. 


BOTANY. 


24. — After  the  formation  of  the  cell-wall  it  generally 
grows,  and  increases  its  surface  and  thickness.     Usually  the 
surface-growth   at  first  preponderates,  afterward    that    in 
thickness.     Neither  the  one  nor  the  other  is  uniform  over 
all  points  of  the  cell-wall,  hence  each  cell  during  its  growth 
may  also  change  its  form.     As  the  growth  of  the  cell-wall  is 
directly  dependent  upon  the  protoplasm,  it  is  clear  that  it 
can  continue  only  as  long  as  the  protoplasm  is  in  contact 
with    its   inner  surface.      In   the 
B  growth  of   the  cell-wall  the  new 

cellulose  secreted  by  the  protoplasm 
[g&^3\      is  deposited  between  the  molecules 
=====4  I      of  the  membrane  already  formed. 

When  the  new  molecules  are  de- 
posited between  the  previously 
formed  ones  only  in  the  plane  of 
the  cell-wall,  surface-growth  takes 
place  ;  but  when  the  planes  of  de- 
position of  the  new  molecules  lie  at 
right  angles  to  the  plane  of  the 
cell-wall,  increase  in  thickness  is 
the  result ;  when  the  molecules  are 
deposited  in  both  planes,  the  wall 
increases  both  in  surface  and  thick- 


0 


1 


Fig.  10.— Diagrams  to  illustrate 


1U.U.  25. — Surface-growth   may    be 

I.AJC  T»C*J  AM  vVnicn,  by  the  noriz1  n-  .  .  T          "    . 

tai  splitting  of  ihe  rmg,  the  ceil  is  terminal  or  intercalary.    In  the  for- 

elongated  ;  z,  the  new  portion  of  ,  -,  ,  -.      . 

the  wail  formed  by  the  splitting  iiier  case  the  growth  is  greatest  at 
c"Vthr8o0cailefdhcaPri^45dij  some  point  on  the  surface,  decreas- 
Sri^TSS^S'S^  ing  in  intensity  on  all  sides.  The 
growing  point  thus  comes  to  pro- 
ject as  a  point  or  knob,  or  it  becomes  the  end  of  a  cylindri- 
cal sac.  If  several  points  of  growth  occur  in  a  cell  it  may 
become  star-shaped,  and  by  a  continuation  of  the  process 
repeatedly  branched.  The  typical  form  of  intercalary 
growth  takes  place  in  definite  belts  which  surround  the  cell, 
as  is  seen  in  (Edogonium  (Fig.  10).  The  growth  of  the 
whole  of  the  side  wall  of  a  cylindrical  cell,  as  in  Spirogyra, 
is  also  a  form  of  intercalary  growth. 


THE  CELL-WALL. 


26. — Growth  in  thickness  of  the  wall  produces  changes 
in  the  cell  of  even  greater  importance  than  growth  in  sur- 
face. While  surface-growth  has  but  little  to  do  with  the 
determination  of  the  functions  of  the  cell,  the  thickening  of 
its  wall  generally  results  in  a 
change  in  function,  or  an  entire 
suspension  of  all  physiological 
activities.  Cells  with  extremely 
thin  walls  are  most  active ;  only 
such  can  take  part  in  growth. 
(See  Chap.  XL)  Nutrition  and 
assimilation  are  confined  to  cells 
whose  Avails  have  but  slight  thick- 
ness. Cells  with  moderately  thick 
walls  may  be  used  as  storehouses 
for  food;  starch,  for  example,  is  x  200.- After  D 
frequently  found  in  such  cells.  But  as  the  walls  attain  great 
thickness  the  protoplasm  loses  all  activity  save  that  neces- 
sary to  the  secretion  of  cellulose. 

27. — The  thickening  generally  produces  certain  markings 
or  sculpturings  in  the  shape  of  projecting  points,  ridges, 
bands,  etc.,  which  on  the  one  hand  are  on 
the  outside  of  the  wall,  while  on  the 
other  they  are  on  the  inside.  In  some 
pollen  grains  and  spores  we  have  the  best 
examples  of  external  markings.  Here,  in 
some  cases,  certain  isolated  points  in  the 
cell-wall  become  strongly  thickened,  giv- 
ing  rise  to  spines  or  prickles  (Fig.  11). 
*n  otner  cases  the  thickening  is  in  cer- 
tilin  bands,  which  may  rise  into  high 
into  a  network."  Eacii  of  walls,  as  in  Fig.  12.  External  markings 

these   bears   thickeuings,  ,  to          „        ... 

which  project  still  more,  occur  only  upon  cells  which  are  free,  or 

in  the  form  of  spines  ar-  .         •..    ,  ,  *  .,,  ,1 

ranged  like  a  comb. —After  in  slight  contact  with  one   another  or 

with  other  cells. 

28. — Internal  markings  are  of  essentially  the  same  kind 
as  the  external,  although  of  greater  variety.  When  the 
secretion  of  new  cellulose  is  greatest  at  isolated  points,  knobs 
and  projections  of  various  kinds  are  the  result.  It  more 


is  fur"ished  with 
like    thickenings 


-,'4 


BOTANY. 


frequently  happens,  however,  that  the  thickening  is  in  bands 
of  greater  or  less  width,  occasionally  extending  over  nearly 
the  whole  inner  surface. 

One  of  the  simplest  cases  is  represented  in  Fig.    13,    where 
new  material  has  been  added  to  all  parts  of  the  wall  ex- 


Pio.  135. 


FIG.  ISA. 


FIG.  14. 


Fig.  18.  —  A,  optical  section  of  a  ederenchyma-cell  from  beneath  the  epidermis  of 
the  underground  tt>  m  of  Pteris  aquilina,  isolated  by  Schulze's  maceration  The 
wall  consists  of  an  inner  very  dense  layer,  and  a  central  less  dense  one  enclosed 
betwren  two  denser  ones;  these  layers  are  penetrated  by  pit  channels,  which  are 
("•en  in  the  further  wall  in  transverse  section.  B,  a  similar  cell,  more  thickened. 
The  pits  are  here  long  cana's,  which  are  more  or  less  branched.  X  about  550.— 
Aft.  r  Sachs. 

Fig.  14.  —  Brown-walled  cells  in  the  stem  of  Pteris  (iquilina.  A,&  half  cell  iso- 
lated and  rendered  colorless  by  Schulze's  maceration.  li,  a  piece  moie  strongly 
magnified  (x  550).  The  fissure-like  pits  are  crossed,  i.e..  the  fissure  is  twisted  as 
th«  thickening  increases  ;  p.  a  side  view  of  a  fissure  appearing  as  a  simple  channel, 
since  it  shows  the  narrow  diameter.  C,  cross-section;  a,  boundary  lamella;  b,  c, 
inner  lamtllse.—  After  Sachs. 

cepting  in  small  isolated  spots.    As  the  wall  thickens  around 
these  spots,  they  become  at  first  pits,  and  finally  channels. 

29.  —  In  some  cases  the  pits  or  channels  are  simple. 
straight,  or  slightly  bent  extensions  of  the  central  cull-cav- 
ity ;  in  others  they  may  be  branched,  as  shown  in  Fig  13#; 
in  cross-section  they  may  be  round,  as  in  Fig.  13  A,  or  elon- 


THICKENINGS  OF  THE   WALL. 


gated  fissures,  as  in  Fig.  14,  or  of  any  form  intermediate 
between  these.  Pits  with  elongated  fissures  may  be  twisted, 
giving  them,  when  seen  in  front  view,  the  appearance  of  two 
fissures  crossing  one  another  (Fig.  14^4,  B). 

3O. — In  the  thickening  of  the  cells  of  the  wood  of  the 
Coniferae  bordered  pits  arc  formed  (Fig.  15).  Here  large 
round  areas  of  the  wall  remain  thin,  and  the  thickening 
mass  arches  over  them  on  all 
sides  in  such  a  way  as  to  form 
low  domes  (Fig.  16,  F]  ;  at  the 
top  of  each  dome  a  small  round 
opening  is  left,  and  this  permits 
free  communication  between  the 
cavity  of  the  cell  and  the  pits 
formed  by  the  dome.  This  pro- 
cess takes  place  in  exactly  the 
same  way  upon  both  sides  of  the 
common  wall  of  contiguous  cells 
(Fig.  16,  B,  t,  t,  and  (7).  When 
the  partition  separating  opposite 
pits  breaks  away,  as  it  generally 
does  quite  soon,  the  resulting  cav- 
ity is  doubly  convex  in  shape 
(Fig.  16,  E).  When  a  pit  of 
this  structure  is  seen  in  front 
view,  it  has  the  appearance  of  two 
concentric  circles  (Fig.  15,  t", 
and  Fig.  16,  D)  ;  the  outer  one 


Fig  15.—Pinus  sylvestris ;  longi- 
tudinal radial  section  through  the 
wood  of  H  rapidly  g  owii'g  branch  ; 


.      ,  * 

being   formed   by   the    bottom    Of   (\  (",('",  bordered  pits,  increasing  In 
,,        °  .,  T     ,/       .  ,         ,,       ase ;  st,  large  pits  where  c  llsof  the 

the    pit,    and    the    inner    by    the  medullary  rays  lie  next  to  the  wood- 

opening  at  its  top. 

The  bordered  pits  of  pines,  firs,  and  other  Coniferae  may  be  readily 
examined  by  making  a  longitudinal  radial  section.  They  are  not  found 
in  abundance  on  the  tangential  surfaces  of  the  cells. 

The  reel  structure  of  the  bordered  pits  of  the  Coniferae  was  not  under- 
stood until  quite  recently.*  Von  Mohl,  apparently  not  noticing  the 

*  Schacht,  in  1859  (Botanische  Zcit>mg,  pp.  238, 239),  and  in  a  memoir 
in  1860  ("De  Maculis  in  Plantarum  Vasis  Cellulisque  Lignosis"),  gave 
the  first  correct  explanation  of  the  structure  of  bordered  pits. 


BOTANY. 


thin  partition,  thought  that  the  lenticular  cavity  was  formed  by  the 
separation  of  the  walls  of  the  two  contiguous  cells  at  that  place,  and  cou- 
A  _  .,  ^  sequently  that  they  were 

intercellular.  This  in- 
terpretation is  still  given 
in  some  books.* 

81.  —  While  the 
bordered  pits  of  the 
Coniferae  are  never 
crowded  together,  in 
the  cells  of  some 
plants  they  are  so 
numerous  as  to  lie 
closely  side  by  side 
(Fig.  17).  In  such 
case  the  first  thick- 
ening of  the  wall  pre- 
sents itself  as  a  net- 
work of  ridges  en- 
closing elliptical  thin 
places.  As  the  thick- 
ening advances  the 
ridges  increase  in 
height,  but  at  first 
not  in  breadth  ;  later 
they  increase  in 
breadth  at  the  top  and 
overarch  the  thin 
areas,  much  as  in  the 

bordered    pits    of  the 

ru«' */„.«,  T«      ±V.,'o 

t-omierae.          In      thlS 

_  ,__  'Umirmroy  f  !-./-> 
CaSC>  hOWCVer,  the 

nr,miino-  of  flin  frm  nF 
Opening  at  t  top  O 

f]lfl  ^if  jo    .,n  plnnP'at- 

rl 

g(J    gjjt    instead    of     a 

. 

Circle      (Fig.     17.      A, 
i   x»  •    \         mi       JT  • 

and  C,  c).     The  thin 


Fig.  16.— Bordered  pits  of  Knus  sylvettris.  A, 
transverse  section  of  mature  wood  ;  ;n,  central  layer 
of  ihe  common  wall;  t,  a  mature  pit  cut  through  the 
middle  ;  t\  the  same,  but  in  a  thicker  part  of  the  sec- 
tion, the  part  of  the  cavity  of  tne  pit  seen  in  perspec- 
tive ;  t",  a  pit  cut  through  below  its  openings;  B, 
transverse  section  through  the  cambium  ;  c,  cambium  ; 
fi,  very  young  wood-cells ;  t,  (,  very  young  bordered 
pits,  seen  in  section  ;  C,  diagram  of  sectional  imd  lat- 
eral views  of  a  young  bordered  pit ;  D,  diagram  of 
sectional  and  lateral  views  of  a  mature  bordered  pit  ; 
E,  section  of  a  mature,  pit,  seen  in  perspective  ;  F, 
section  of  a  younger  pit  seen  in  perspective.  A  and 
B  x  800. -After  Sachs. 

plate  separating  opposite  bordered  pita  of  this  kind  breaks 

*  See  Le  Mnout  and  DecaisneV  Traite  Generate  de  Botanique,"  1868 
[English  edition,   1872]  ;   UHffitli  and  Hentrey's  "  Micrographic  Die. 


THICKENINGS  OF   THE   WALL. 


away  as  in  the  previous  case,  and  so  free   communication 
between  adjacent  cells  or  vessels  is  established. 

B 


FIG.  18. 

Fig.  ir.— Bordered  pits  of  the  thick  root  of  Dahlia  variaUlls.  A,  front  view  of  a 
piece  of  the  wall  of  a  vessel,  seen  from  without ;  B,  transverse  section  of  the  same 
(horizontal,  and  at  right  angles  to  the  paper) ;  C,  longitudinal  section  of  A  (vertical, 
and  at  right  angles  to  the  paper)  ;  q,  septum  ;  a,  the  original  thin  thickening-ridge  ; 
6,  the  expanded  part  of  the  thickening  masses,  formed  later  and  overarching  the  pit ; 
«,  thu  fissure  through  which  the  cavity  of  the  pit  communicates  with  the  cell  cavity  ; 
at  «  and  ,3  the  corresponding  front  view  is  appended,  in  order  to  make  the  trans- 
verse and  longitudinal  sections  more  clear,  x  800.— After  Sachs. 

Fig.  18.— Scalariform  thickening  of  the  walls  of  a  vessel  from  the  underground 
stem  of  Pteris  aquilina.  A,  half-vessel,  i  soli  ted  by  Schulze's  maceration  ;  £  to  D, 
pieces  obtained  from  stemn  hardened  in  absolute  alcohol ;  S,  a  partly  diagrammatic 
view  of  a  vertical  section  of  the  wall,  seen  from  within  ;  c,  c,  plan  of  section  ;  rf, 
opening  to  pit ;  C,  front  view  of  young  wall  of  a  vessel  ;  «,  unthickened  portion  of 
wall;  v,  thickening-ridge;  Z>,  vertical  section  of  C;  ^section  of  wall  in  a  place 
where  a  vessel  adjoins  a  succulent  cell  p;  the  thickening-ridges  (g)  are  only  on 
one  side.  X  800.— After  Sachs. 

tionary,"  third  edition,  1874;  Carpenter's  "The  Microscope,"  fifth  edi 
tion,  t874. 


BOTANY. 


32. — The  passage  from  the  mode  of  thickening  just  de- 
scribed to  the  scalariform  manner  (Fig.  18)  is  an  easy  one. 
Here  each  longitudinal  angle  of  the  cell  or  vessel  is  thickened, 
and  from  these  thickened  angles  ridges  run  right  and  left, 
from  one  to  the  other  (Fig.  18,  C,  v).  The  after  growth 
of  the  ridges  is  essentially  the  same  as  in  the  case  of  crowded 
pits  ;  in  fact,  the  pits  here  are  simply  greatly  elongated  and 
crowded  bordered  pits.  Eventually  the  narrow  plates  be- 
tween the  thickened  ridges  disappear,  as  in  the  other  cases. 
Examples  of  scalariform  thickening  are  common,  especially 
in  the  ferns. 

33. — The  development  of  rings  (Fig.  19,  v)  is  nearly  like 
that  of  the  scalariform  thickening.  Instead,  however,  of 


Fig.  19.— Longitudinal  section  of  a  portion  of  the  stem  of  Impatiens  Baltamiiui. 
v,  annular  vessel,  v',  a  vessel  with  thickenings  which  are  partly  spiral  and  partly  an- 
nular ;  v",  v'",  v"",  several  varieties  of  spiral  vessels ;  v'"",  a  reiiculated  vessel- 
After  Dnchartre. 

the  ridges  being  short,  they  extend  entirely  around  the  inner 
surface  of  the  wall.  The  transition  from  rings  to  spirals  is 
a  simple  one,  the  thickening  taking  place  in  a  spiral  line, 
instead  of  in  one  passing  directly  around  the  wall  (Fig.  19, 
v",  v'").  Transitional  forms  are  frequently  found  (Fig.  19, 
v'),  and  many  modifications  and  irregularities  occur — e.g., 
in  the  figure  at  v'""  is  the  form  known  as  the  reticulated. 

34. — In  all  the  foregoing  cases  the  marking  of  the  wall 
has  been  general ;  there  are  some  cases,  however,  where  it 
is  localized.  A  good  example  of  this  is  in  the  formation  of 
the  pits  of  sieve-cells  (Fig.  20).  The  horizontal  walls,  and 
also  areas  upon  the  longitudinal  ones,  become  thickened 
reticulately,  leaving  rather  large  thin  areas,  as  shown  in 
Fig.  20,  q,  q.  After  a  while  the  thin  areas  become  absorbed, 


THICKENINGS  OF  THE   WALL.  29 

allowing  the  protoplasm  of  contiguous  cells  to  become  struc- 
turally united.  The  sieve- like  appearance  of  these  modified 
portions  of  the  wall  give  to  the  Cells  their  name  of  sieve-cells. 

35.— The  collen- 
chyma  cells  which 
are  frequently  found 
beneath  the  epider- 
mis of  the  succulent 
parts  of  h  i  g  h  e  r 
plants  afford  an- 
other instance  of 
localized  thicken- 
ing. Here  only  the 
angles  of  the  cells 
become  thickened, 
leaving  broad  por- 
tions of  the  wall  un- 
modified (Fig.  21). 

(a)  Examples  of  the 
uniform  thickening  of 
the  cell-wall  may  be 
obtained  for  study  by 
making  thin  sections  of 
the  hard  parts  of  many 
nuts  and  seeds  (Figs.  58 
to  61) ;  in  many  of  these 
more  or  less  complex 
channels  may  be  found. 
Bordered  pits  are  best 
studied  in  longitudinal 
sections  of  the  young 
wood  of  the  pines,  firs,  Fig.  20.— Young  sieve  tubes  of  Ciicurbi/a  pepo  The 
tf  anr\  tlie  r»rnwrlprl  drawing  made  from  specimens  whirh,  bv  having  lain  a 
etc.,  and  the  crowded  !„,,„  time  in  absolute  alcohol,  have  allowed  the  produc- 
pits  in  the  steins  of  tion  of  •.•xiremely  clear  sections;  g,  transverse  view  of 
tl  Tji  tieve-like  septa ;  xi,  sieve  plate  on  side  wall  ;  aj,  thin- 

most    other     Phanero-  ner  parts  of  the  loagifeMjind  vvai| ;  ;,  the  same  seen  in 
o-ams          Longitudinal   section  ;  ps,  contracted  protoplasmic  contents   (lifted 
,  off  at  gp  from  the  transverse  septum,  still  in  contact 

sections  of  the  stems  of  ats/) ;  z,  parenchyma-cells  between  sieve-tubes,  x  550. 
most  annuals  will  yield  -After  Sachs. 

good  examples  of  ringed,  spiral,  and  reticulated  thickening.  The 
stems  of  the  Cucurbitacese  (Pumpkin,  Squash,  Gourd,  etc.)  furnish  fine 
examples  of  sieve  cells  and  collenchyma. 

(6)  In. this  place  msiy  be  mentioned  the  curious  and  sometimes  puz- 


30 


BOTANY. 


zling  hernioid  protrusions  to  be  met  with  in  some  plants.  When  the 
surrounding  cells  are  very  active,  it  sometimes  happens  that  the  thin 
membrane  which  closes  up  a  pit  grows  and  is  pushed  through  into 


in  the  lower  fig- 
ure (Fig.  21a), 
where  th  repre- 
sents the  thicken- 
ed portion  of  the 
wall,  and  tea  the 
thin  portion  clos- 
ing the  pits.  Oc- 
casionally many 
such  protrusions 
enter  the  vessel,  as 
in  a  in  the  upper 
figure  ;5f  these  be- 
come large  they 
may  entirely  fill 
up  the  cavity  of  Fig.  21.— Collenchyma  cells  of  the  Begonia,  transverse  see- 
fi  ool  oo  o+  7.  tion  of  the  petiole,  e,  epidermis  ;  e/,  collenchyma-cellf,  with 

tlie  vessel,  as  at  0,    thickened  angles,  r>,v, •  chl.  chlorophyll-bodies  ;p,  large  cell  of 
where    two    large    parenchyma,     x  550.— After  Sachs. 

,  Fig.  21a.— Hernioid  protrusions  into  the  pitted  vessels  of 

ones  from  opposite    Echfnorytti*  lobata  ;  the  upper  figure  magnified  250,  and  the 
sides  have  met.         lower  lOOO.— From  drawings  by  J..  C.  Arthur. 

36.— Theories  as  to  the  Mode  of  Thickening.    The  real 
nature  of  the  process  in  the  growth  in  surface  and  thickness 


THICKENINGS  OF  THE   WALL.  31 

of  the  cell-wall  was  for  a  long  time  not  fully  understood. 
There  have  been  three  prominent  theories  advanced  to  ex- 
plain the  phenomena  observed.  They  may  be  briefly  stated 
as  follows  : 

I.  Von  Mohl  held  that  "the growth  of  the  cell-membrane 
in  thickness  arises  from  a  periodical  apposition  of  new  mem- 
branes upon  the  already  completely  developed  wall."*     Ac- 
cording to  this  theory,  the  marks  of  stratification  usually  seen 
were  supposed  to  be  the  lines  separating  the  added  mem- 
branes.    This  deposition  was  supposed  to  proceed  from  with- 
out inwards  ;  that  is,  the  newer  layers  were  supposed  to  be 
placed  inside  of  the  previously  existing  ones  ;  on  this  ac- 
count this  has  been  called  the  theory  of  centripetal  thicken- 
ing.    Until  quite  recently  this  has  been  the  prevailing  theo- 
ry in  English  and  American  books. 

II.  Some  observers,  among  whom  were  Hartig  and  Hart- 
ing,  laying  great  stress  upon  the  external  markings,  as  seen 
in  pollen  grains,  spores,  etc.,  opposed  the  foregoing  theory, 
and  propounded  one  which  has  been  termed  the  theory  of 
centrifugal  thickening.    According  to  this  theory,  "  the  cell- 
membrane   increases  in  thickness   in    the    direction  from 
within  outwards  by  the  deposition  of  layers  upon  the  out- 
side of  the  original  membrane."     It  is  thus  the  exact  oppo- 
site of  the  previous  one ;  while  in   the  former  the  outer 
membrane  is  supposed  to  be  the  oldest,  in  the  la*tter  it  is  the 
inner  one. 

III.  The  theory  which  now  generally  prevails  is  that  the 
thickening  of  the  wall  is  a  growth,  due  to  the  formation  or 
deposition  of  new  molecules  between  the  molecules  of  the 
original  membrane.     It  is  called  the  theory  of  intussuscep- 
tion, and  was  originated  by  Nageli  in  1858.  f 

*  The  student  will  find  a  condensed  statement  of  this  theory  in  the 
"  Principles  of  the  Anatomy  and  Physiology  of  the  Vegetable  Cell,"  by 
Hugo  Von  Mohl,  translated  by  Henfrey,  1851. 

f  Nageli,  "  Die  Starkekorner,"  in  "  Pflanzenphysiologischen  Unter- 
suchungen,"  1858.  Duchartre  claims  for  Trecul  the  first  suggestion  of 
this  theory  in  1854.  The  term  intussusception  as  applied  to  the  growth 
of  the  cell-wall  was  used  long  before  this  ;  Schleiden,  in  his  "  Contri- 


32  BOTANY. 

37. — Every  part  of  the  living  cell-wall  appears,  from  the 
results  of  Nageli's  researches,  to  be  composed  of  definite 
molecules,  which  are  not  in  contact,  but  separated  from  one 
another  by  layers  of  water,  termed  the  Water  of  Organiza- 
tion. The  thickness  of  these  intermolccular  layers,  and  con- 
sequently the  amount  of  water  in  the  whole  mass  of  any  cell- 
wall,  v.iries  in  different  cells,  and  even  in  the  same  cell.  In 
the  denser  walls,  or  parts  of  walls,  the  water  is  less  ;  in  those 
which  are  less  dense  it  is  greater.  (Fig.  22.) 

Now  it  is  evident  that  young  cell-walls  must  have  rela- 
tively large  amounts  of  water  in  their  substance,  and  here  is 
where  we  find  a  growth  taking  place.  Sachs  supposes*  that 
an  aqueous  solution  derived  from  the  protoplasm  penetrates 
by  diffusion  between  the  molecules  of  the  cell-wall.  This  is 
not  a  solution  of  protoplasm,  but  probably  some  carbohy- 
drate constituent  of  the  protoplasm  which  is  easily  trans- 
formed into  cellulose.  From  this  nutrient  solution  there 
may  be  formed  in  the  spaces  filled  with  water  new  molecules 
of  cellulose,  which  push  aside  and  separate  the  previously 
formed  ones ;  or  the  previously  formed  molecules  may  be 
simply  enlarged  by  the  apposition  of  new  matter. 

According  to  the  theory  just  described,  the  formation  of  any  projec- 
tion upon  the  inner  surface  of  the  cell -wall  is  not  by  the  superficial 
deposition  of  molecules  upon  any  definite  area  of  the  surface  of  the 
wall,  but  by  tlie  abundant  and  continued  deposition  of  new  molecules 
in  the  wall ;  it  consequently  becomes  thicker  at  the  place  of  deposi- 
tion ;  in  this  thickened  portion  still  more  molecules  are  deposited,  and 
the  thickness  is  further  increased,  and  so  on.  In  the  same  way  projec- 
tions are  foniie'J  upon  the  outside  of  the  wall  by  a  slow  internal  growth. 

38.— Stratification  of  the  Wall.  During  the  increase  of 
the  cell-wall  in  thickness,  an  appearance  of  stratification 
arises  in  it  (Fig.  23).  A  cell-wall  in  which  this  is  strongly 
developed  appears  to  be  made  up  of  concentric  layers,  and 
this  no  doubt  gave  rise  to  the  two  theories  before  men- 

butions  to  Phylogenesis,"  1838,  makes  use  of  the  word,  but  it  may  be 
doubted  whether  he  or  Trecul  gave  it  exactly  the  meaning  we  now  do. 
*  "  Lehrbuch,"  fourth  edition,  and  the  English  translation  of  the 
third  edition  ("  Text-Book  of  Botany  "),  Books  I.  and  III. 


STRATIFICATION  OF  THE   WALL. 


33 


tioned,  in  which  the  thickening  was  supposed  to  be  due  to 

the  successive  deposition  of  layers,  either  inside  or  outside  of 

the  original  wall.    It  is  now  known  that  stratification  is  due 

to    a   subsequent 

change      in     the 

amount  of  water 

of      organization 

present  in  partic- 

ular parts  of  the 

wall.    When  seen 

with  the    micro- 

scope, those  layers 

which  contain  the 

most  water,   and 

•Mr*    4-1*  Fig.  22.—  Diagrammat.c  figure  to  Illustrate  Nagcli's  the- 

COllSequeiltly    the  ory  of  the  molecular  structure  of  the  cell-wall  ;  m,  m,  m, 

lpa«f  ppllnlnap    QVO  the  crystal  molecules  ;  w.  w,  w,  the  layers  of  water  which 

HUbC,  die  separate  the  moli-cules.    The  water  layers'  are  represented 

]    „„     ofrnno-lv    VP  as  very  thin  ;  the  v  are  frequently  much  thicker  m  propor- 

16SS     Strongly    re-  tjon  to  tne  diameter8  of  Se  molecules.    <No™.-fi  must 

fractive     than  be  borne  in  mind  that  tnis  figure  is  purely  diagrammatic.) 

those  which  contain  less  water,  or  which,  in  other  words,  are 

denser. 

39.  Striation.  —  In  many  cases  there  is  also  a  similar  sepa- 
ration into  more  watery  and  less  watery 
layers  at  right  angles  to  those  just 
mentioned.  There  may  be  one  system 
of  such  differentiation,  giving  rise  to  a 
transverse  striation,  which  may  be  an- 
nular (Fig.  24,  c,  d,  e)  or  spiral  (a,  b)  ; 
or  there  may  be  two  systems,  and  then 
the  wall  appears  to  be  crossed  by  two- 
rig.  ss.-Trangverse  sec-  sets  of  spirals  which  run  in  opposite 

tion  of  a  ba*t  fibre  of  the    /Urppfi'nn<5  arnrmrl  flip  PA!! 

thickened  root  of  Dahlia,  directions  arouna  tne  ceil. 

Goo&  examples  of  stratification  may  be  found 
in  the  Pith-cells  of  the  root  of  the  dahlia,  and 
ner  system  of  layers  has    in  tlie  epidermal  cells  of  most  thick  leaves  ;  and 


2T,  pit  channel*  which  penl 


-If  ter  S8achsrated' 


X  8°°'  of  8triation  in  tbe  bast-cells  of  the  periwinkle 
(  Vinca  major),  and  the  wood  of  the  Douglas 
Spruce  (Tsuga  l)ouglasii).  In  many  cases  it  is  necessary  to  treat  the 
specimens  with  such  jjcids  (e.g.,  sulphuric  acid)  or  alknlies  (e  g.,  caus- 
tic potash)  as  will  produce  swelling. 


34 


BOTANY. 


40.— Formation  of  Chemically  Different  Layers.  A  still 
further  differentiation  may  take  place  in  the  thickened  wall, 
by  which  it  comes  to  be  made  up  of  layers  which  differ 
chemically  from  one  another.  This  is  brought  about  by 
the  subsequent  infiltration  of  diverse  materials  into  different 
layers.  In  some  cases  the  chemical 
change  is  accompanied  by  so  great  a 
physical  change  that  the  wall  sepa- 
rates readily  into  two  or  more  plates.  * 
Thus,  in  pollen-cells,  the  original  Avail 
is  usually  differentiated  into  two  wide- 
ly differing  plates  :  (1)  an  outer  thick 
cuticularized  covering  (the  extine), 
and  (2)  a  thin  inner  membrane  (the 
intine) ;  the  inner  plate  is  shown  by 
tests  to  be  composed  of  pure  cellulose, 
while  the  outer  one  is  generally  so 
filled  with  other  materials  as  to  hide 
completely  the  cellulose. 

A  similar  differentiation  of  the  wall 
takes  place  in  certain  spores,  and  in 
such  case  the  outer  plate  is  called  the 
exospore  (or  epispore),  and  the  inner 
one  the  endospore  (see  C,  D,  E,  F, 
Fig.  180,  p.  262). 

The  outer  walls  of  the  epidermal 
celk  of  many  plants  show  a  remark- 
able separation  into  one  or  more 
plates,  the  outermost  of  which  is 
highly  cuticularized.  In  some  cases, 
as  in  the  cabbage,  for  example,  this 
rig.  24.—  striation  of  the  outer  plate  may  easily  be  separated  as 

bast  fibres  of  Ifoya  camota •  ;  r.  *••  »         ,1 

a  and  b,  crossed  annular  stri-  a    COlltlllUOUS    pellicle — the    SO-Called 

ation  ;  c,  d,  e,  varieties  o  sim-          ,.   , 

pie   annular   e'riation.— After  Cuticle. 

Wood-cells  frequently  shoAv  a  well- 
marked  separation  into  plates.  This  may  be  seen  in  Finns 
sylvesfris  (Fig.  16,  p.  26),  where  there  are  three  such 


*  These  are  the  "  Schalen  "  of  Sachs,  translated  "  Shells  "  in  the  Eng- 
lish edition  of  his  "  Lehrbuch." 


DIFFERENT  LAYERS  IN  THE   WALL.  35 

plates,  viz.,  a  thin  inner  one  (i),  a  thicker  middle  one  (z), 
and  a  thin  outer  one  (in).  The  latter  is  apparently  common 
to  the  two  contiguous  cells,  and  is  the  "  primary  cell- wall " 
of  some  authors  and  the  "  intercellular  substance"  of  others. 

The  deportment  of  these  layers  on  the  application  of  reagents  is 
interesting. 

1.  On  treatment  with  a  solution  of  iodine  the  outer  and  middle  plates 
turn  yellow. 

2.  On  treatment  with  iodine  and  sulphuric  acid  the  outer  and  middle 
plates  turn  yellow  and  the  inner  one  blue. 

3.  On  treatment  with   concentrated   sulphuric  acid  the  inner  and 
middle  plates  are  dissolved,  while  the  outer  remains. 

4.  On  boiling  in  nitric  acid  with  potassium  chlorate  the  outer  plate 
is  dissolved,  while  the  middle  and  inner  are  not.     By  this  latter  process, 
called  "  Schulze's  Maceration,"  the  cells  may  be  isolated,  but  it  must 
be  borne  in  mind  that  such  isolated  cells  have  lost  by  sol ution  their 
outer  plate. 

41. — In  some  cases  the  differentiation  is  of  such  a  nature 
that  one  or  more  plates  become  converted  into  mucilage  in 
water.  In  the  dry  state  the  mucilaginous  portions  are  hard 
and  cartilaginous.  Examples  of  the  change  of  the  outer  plates 
into  mucilage  are  common  in  the  Fucacese,  and  of  a  sim- 
ilar change  of  the  inner  ones  in  the  seeds  of  flax  and  quince.* 

42. — Incombustible  Substances,  as  silica  and  lime,  are 
frequently  deposited  between  the  molecules  of  cellulose  in 
the  wall.  Cell-walls  which  are  filled  with  considerable  quan- 
tities of  these  substances,  upon  burning,  leave  ash-skeletons, 
which  retain  the  form  and  markings  of  the  cell.  The  Di- 
atoms furnish  excellent  examples  of  highly  silicified  walls. 
Silica  is  abundant  also  in  the  epidermal  cells  of  grasses 
and  scouring- rushes  (Equisetacece). 

Lime-skeletons  may  be  obtained  by  the  combustion  of  thin  slices  of 
the  tissues  of  many  plants  upon  glass  °r  platinum-foil.  The  vessels  of 
Cucurbita  Pepo  yield  (according  to  Sachs)  beautiful  skeletons  under  this 
treatment. 

Silica-skeletons  may  be  obtained  by  first  soaking  the  tissue  in  nitric 
or  hydrochloric  acid  and  then  burning,  or  by  burning  (upon  platinum- 
foil)  in  a  drop  of  sulphuric  acid. 

*  Sachs  attempts  to  reduce  the  chemical  differentiations  of  the  cell- 
wall  to  three  categories,  viz.,  Outicularizing,  Lignification,  and  Conver 
sion  into  Mucilage. 


CHAPTER  IV. 

THE  FORMATION   OF  NEW    CELLS. 

43. — There  are  two  essentially  different  ways  in  which 
cells  originate,  viz.,  (1)  by  the  division  of  a  protoplasmic 
body  into  two  or  more  bodies ;  (2)  by  the  union  of  two  or 
more  protoplasmic  bodies. 

44.— Cell-Formation  by  Division.  The  simplest  cases  of 
the  formation  of  cells  by  division  occur  in  the  Myxomy- 
cetes.  The  swarm-spores  (a,  Fig  25),  Avhich  are  naked  masses 
of  freely  moving  protoplasm,  first  lose  their  nuclei  (as  in  Z>), 
and  then  become  constricted  (as  at  c) ;  the  constriction 
deepens,  and  finally  dhides  each  mass 
into  two  parts  (d,  e,f). 

45. — This  may  be  taken,  as  the 
type  of  cell-formation  by  division, 
and  in  no  case  does  it  differ  in  any 
essential  particular  from  this.  Most 
plant-cells,  however,  are  surrounded 
by  a  Avail,  whose  deportment  during 
division  enables  us  to  distinguish  two 

begun  •*«./,  completion  of  ™™  ™  less  well-marked  modes  of 
the  Process.-Aftcri>e  Bury,  cell-form ation  by  division.  On  the 
one  hand  the  wall  divides  as  Avell  as  the  protoplasm  (Fission}, 
while  on  the  other  the  wall  takes  no  part  in  the  division,  and 
it  is  only  the  protoplasm  which  divides  (Infernal  Cell-For- 
mation}. 

46. — The  best  examples  of  Fission  are  to  be  seen  in  those 
unicellular  plants  which  have  been  frequently  described 
under  the  name  of  Protococcus.*  "The  cell  elongates  and 
the  protoplasm  divides  into  two  across  its  longer  axis,  and 


Fig.  25.  — Division  of  the 
swarm-spores  of  C'fioniModer- 
mu  di/onne ;  a,  with  nucleus  ; 
6.  nucleus  dlMolved  ;  c.  two 
nuclei,  division  of  protoplasm 


ee  "Huxley  and  Martin's  Biology,"  Clinp.  II. 


CELL  FORMATION  BY  DIVISION.  3? 

then  a  partition  is  formed  subdividing  the  sac  ;  the  halves 
either  separate  at  once  and  each  rounds  itself  off  and  becomes 
an  independent  cell,  or  one  or  both  halves  again  divide  in  a 
similar  way  before  they  separate,  and  so  three  or  four  new- 
cells  are  produced." 

47.  —  In  many  of  the  filamentous  Thallophytes  a  similar  fis- 
sion takes  place,  but  in  these  the  cells  do  not  immediately  sepa- 
rate from  one  another  after  their  formation.    Thus,  in  Nostoc 
and  Oscillatoria  (Fig.  26)  the  cells  do  not  differ  in  any  essen- 
tial way  as  to  their  formation  from  those  which  constitute 
Protococcus.     In  Nostoc  after  fission  the  cells  round  them- 
selves up  and  retain  but  a  slight  and  easily  separable  connec- 
tion with  one  another  ;  in 

Oscillatoria,  on  the  con- 
trary,  the  cells  remain  cy- 
lindrical and  are  less  read- 
ily separable. 

48.  —  111  SpirOUljra  (Fig.       Fig.  M.-A,  filament  of  Nottoe;  B,  filament 


36,  p.  45)  new  cells  form  <  -    x  aoo.-After  Prami. 

by  the  partition  of  old  ones.  The  protoplasmic  sac  infolds  all 
around  the  middle  of  the  old  cell  Avhich  is  cylindrical  in 
shape  ;  into  the  circular  channel  thus  formed  the  cell-wall 
extends,  appearing  at  first  as  a  narrow  projection  from  the 
original  wall,  but  becoming  broader  and  broader,  until  it 
forms  a  complete  partition.  When  the  new  cells  have 
elongated  by  intercalary  growth  the  process  of  fission  may  be 
repeated,  and  so  on.* 

49.  —  The  cells  which  make  up  the  greater  part  of  the 
tissues  of  the  higher  plants  are  formed  by  fission.  In  the 
apical  cells  of  Equisetum  we  find  a  curious  regularity  in  the 

*  The  student  is  referred  to  Sachs'  "  Text-Book,"  pp.  17-18,  for  a  further 
description  of  this  process  in  Spirogyra  ;  and  to  Von  Mohl's  "  Anatomy 
and  Physiology  of  the  Vegetable  Cell,"  pp.  50-51,  for  a  description  of  the 
similar  fission  of  Cladophora  glomerata  (Conferva  glomerata,  Linn.).  Von 
Mohl's  description,  which  was  the  result  of  the  first  accurate  investiga- 
tion of  cell-  formation,  is  erroneous  in  this  —  that  he  supposes  that  during 
the  process,  to  quote  his  words,  "  a  cellulose  membrane  is  deposited  all 
over  the  outside  of  the  primordial  utricle"  of  the  whole  cell,  and  thnt 
it  is  a  portion  of  this  new  membrane  which  forms  the  partition. 


38  BOTANY. 

division.  The  triangular  apical  cells  of  the  growing  stems? 
divide  repeatedly  in  the  manner  shown  in  the  diagram  (Fig. 
27).  Here  the  cell  A  B  C,  bounded  by  the  heavy  black 


Fig.  27.— Diagram  to  show  mode  of  fission  of  the  apical  cell,  as  seen  from  above. 
7,  the  cell  A,  £,  C,  divided  by  the  partition  1  ;  //,  the  t-ame  cell  with  a  second  par- 
tition, 2  ;  ///,  the  same  cell  with  a  third  partition,  3. 

lines,  is  first  divided  into  tAvo  unequal  portions  by  the  parti- 
tion 1, 1.  ;  next  the  larger  portion  of  the  divided  cell  is  again  ' 
divided  by  the  partition  2,  II.  ; 
later,  a  third  partition  (3,  III.) 
is  formed,  and  so  on.  It  is  no- 
ticeable that  in  this  case  the 
partition  always  forms  parallel 
to  the  oldest  wall  of  the  divid- 
ing cell.  By  continued  growth 
the  apical  cell  retains,  despite 
its  repeated  divisions,  its  origi- 
nal dimensions. 

50. — The  growing  cells  of  the 
stem  of  the  English  bean  (  Vicia 
faba)  furnish  a  good  illustration 
of  fission  in  the  highest  plants. 
In  this  case,  and  in  many 
other,  if  not  all,  Dicotyledons, 
the  division  takec  place  directly 
through  the  centrally  placed 


Fig.  28.-Meri8tem-cells  of  the  stem 
of  nciafaba,  in  procees  of  fission ;  in 


the  cells  a,  a,  the  process  is  in  Us  nucleus  (a,  Fig.  28).  After  the 
earlier  st age ;  at  b  it  is  completed,  x  .  *  '  °  „  , 

300.— After  Pranti.  formation  of  the  new  wall  each 

new  nucleus  moves  away  and  occupies  a  position  on  the 
opposite  side  of  the  cell  from  where  it  was  formed  (as  at  J 
and  k). 


CELL  FORMATION  7?F  DTVISION.  39 

(a)  The  foregoing;  must  suffice  as  examples  of  Fission.  It  occurs 
throughout  the  vegetable  kingdom  and  may  be  regarded  as  the  great 
Hieans  by  which  cells  are  multiplied. 

(6)  The  cambium  zone  of  Dicotyledons  may  be  examined  very  profit- 
ably by  the  student.  If  a  thin  cross-section  of  a  stem  be  soaked  for  a 
Short  time  in  a  carmine  solution,  the  protoplasm  of  the  cambium  zone 
will  be  colored,  and  the  newly  formed  partitions  made  thus  more 
distinct. 

(c)  The  ends  of  young  roots  are  valuable  for  study  ;  longitudinal  sec- 
tions of  these  should  be  made,  and  treated  as  in  the  previous  case. 

(d)  Another  interesting  study  of  a  special  kind  of    fission   may  be 
taken  up  in  an  examination  of  the  development  of  stomata.    (See  p.  99.) 

(e)  That  slight  variation  of  fission,  which  has  sometimes  been  called 
budding,  may  be  very  easily  studied  in  the  Yeast  Plant  (Saccharomycrs 
cerevmce)*   The  conidia,  stylospores,  and  basidiospores  of  many  fungi, 
which  are  more  difficult  to  study,  are 

very  instructive  examples  of  this  va- 
riety of  fission.  Conidia  may  be 
studied  in  Cystopus ;  stylospores  in 
the  Red  Rust  of  the  grasses  (the  so- 
called  uredo-stage  of  Puccinia  gram- 
inis)  ;  and  basidiospores  in  young 
toadstools  (Agaricus). 

61.-Tho  Yeast  Plant  (Sac- 
cliaromyces  cerevisice)  furnishes 

a  VPVV  snmiYIp  p \-flrmiln  of   Tutor      cells   from  "toP  yeast;"    c,  bottom 

a  \ei}  simple  example  -   yea8t  after  cultfva,ion  on  a  piece  <  t 

lial      Cell  -  Formation.        Under    carrot  four  cells  forming  tatbe  tote- 

nor  of  the  jiarent  cell ;   d,  the  fonr 

Certain  Conditions  the  Cells  STOW     danghter-cells ;  a  and  b  X  400,  c  and  cl 
3     ,        X  750.— Alter  Reees. 

to    a    larger   size   than   usual ; 

their  protoplasmic  contents  divide  into,  generally,  four 
parts  (one  to  four,  according  to  Sachs),  each  of  which 
rounds  itself  up  and  secretes  a  wall  of  cellulose  on  its  sur- 
face (Fig.  29,  c,  d).  Cells  which  divide  in  this  way  are  called 
mother-cells,  and  the  new  ones  formed  from  them  daughter- 
cells.  In  the  Yeast  Plant  after  the  daughter-cells  are  fully 
formed  the  dead  wall  of  the  mother-cell  breaks  up. 

52. — The  terminal  cells  of  Achlya  (one  of .  the  Sapro- 
leyniacece)  form  large  numbers  of  daughter-cells  by  the 
breaking  up  of  the  protoplasm,  as  shown  in  Fig.  30,  A. 
When  the  danghter-cells  escape  they  become  rounded  (B,a); 


See  "  Huxley  and  Martin's  Biology,"  Chap.  I. 


40 


EOT  ANY. 


after  a  little  while  they  break  their  cellulose  walls  and  be- 

come naked  motile  cells  (/oospores)  (B,  e). 

53.  —  As  the  formation  of  the  spores  of  Bryophytes  and 
Pteridophytes,  and  of  the  pollen- 
cells  in  Phanerogams,  is  essen- 
tially alike,  we  may  take  as  an 
example  the  formation  of  the 
spores  of  a  fern  (Fig.  31).  The 
nucleus  of  the  mother-cell  first 
disappears,  and  two  new  nuclei 

\\9  \  arise  P''  IL'  IIL)  ;  between  the 

\^    \       I.;  nuclei  may  be  seen  a  line  indicat- 

\  mi.  \  lelirei  ing  the  separation  of  the  proto- 
plasmic mass  into  two  halves. 
Xext  the  nucleus  in  eacli  half  is 
absorbed  and  replaced  by  two, 
between  which  a  separation  of  the 
protoplasm  soon  takes  place  (IV., 
V.),  thus  dividing  the  cell  into 
four  equal  parts,  which  are  at 
first  angular,  but  soon  rounded 
and  enclosed  in  cell-walls  (VI., 
VII.,  VIII.  ,  IX.). 

54.  —  In  the  foregoing  cases  the 
whole  of  the  protoplasm  of  the 
mother-cell  is  used  in  the  forma- 
tion of  the  daughter-cells.  There 
are  some  cases,  however,  in  which 
only  a  part  of  the  protoplasm  is 

Fi?.  SO.-Terminal  cells  of  Achlya.   used.       One  of   the  best    known    is 


c  in   the   formation   of  ascospores. 


thc 


^  ;  Here  the  mother-cells  are  usually 


of   the  daughter  cells,  from  which  ])    A   '  the  nucleus  disappears,  and 
the  content*  have  i-sciipert  as  motile     ,  ,  .  .    '  , 

ceils  (/.oos-pore^,  «,•  c,  a  young  lat-  the  ])roto])lasm  condenses  in  tlie 

era,  branch,     x  850.-  After  Sachs. 


in  some  cases  (not  in  the  species  figured)  nuclei  appear,  and 
about  these  portions  of  the  protoplasm  gather  to  form  the 
ascospores  ;  in  other  cases  (Fig.  32)  the  protoplasm  condenses 


CELL  FORMATION  BY  DIVISION. 


41 


about  certain  points  without  the  previous  formation  of  nu- 
clei (d,  e).  In  either  case  firm  Avails  are  secreted  about  the 
spores  while  yet  in  the  mother-cell  and  surrounded  by  the 
unused  part  of  its  protoplasm. 

55.  —  The  most  striking  example  of  this  variety  of  internal 
cell-formation  is.  to  be  found  in  the  development  of  the 
endosperm  cells  in  the  embryo  sac  of  Phanerogams.  The 
protoplasm  which  occupies  the  cavity  of  the  embryo  sac  pre- 
sents here  and  there  points  of  condensation  or  concentration, 
which  in  a  little  time  become  as  many  nuclei  (Fig.  33,  A,  n,  n), 
each  containing  a  nncleolus.  These  nuclei  are  the  first  in- 
dications of  the  form- 
ing cells.  Protoplasm 
gathers  about  the  nu- 
clei and  forms  globu- 
lar or  ovoid  masses 
(A,  a,  a),  which,  after 
acquiring  a  certain 
size,  secrete  a  thin 
Avail  of  cellulose  on 
their  surfaces  (A,  c,  c', 
d).  By  the  continued 
production  of  new 
cells  within  the  em- 
bryo sac,  in  this  Avay, 
they  finally  become 
crowded  together  into 
a  loose  tissue,  in  whose  intercellular  spaces  portions  of  the 
unconsumed  protoplasm  yet  remain  (B}.  After  their  forma- 
tion the  cells  go  on  increasing  in  numbers  by  simple  fission 


Fig.  31.— Development  of  thn  pporee  of  Atjndium 
fillx-mas.  /.the  spore-mot her-ceil,  with  nucleus; 
//,  the  nucleus  absorbed  ;  ///,  two  nuclei,  and  the 
division  of  the  protoplasm  into  two  portions ;  IV, 
four  nuclei  ;  V.  division  o£  the  protoplasm  into  four 
portions  ;  VI,  VII,  VIII,  rounding  up  of  the  young 
spores  during  the  sccri-tiou  of  their  cell-walls  ;  IX, 
mature  s^pore,  with  thick  and  sculptured  exospore 
(epispore).  X  550.— After  Sachs. 


(a)  Sachs  f  makes  a  strong  distinction  between  the  cases  of  internal 
cell-  formation  where,  on  the  one  hand,  a  part  only,  and,  on  the  other, 

*  The  student  is  here  referred  to  the  account  of  the  formation  of 
endosperm  cells  in  Duchartre's  "Elements  de  Botanique,"  pp.  37-39  ; 
and  also  to  Hofmeister's  "  Lehre  von  der  Pflanzenzelle,"  Section  17. 

f  "  Lehrbnch,"  4te  auf.  In  the  English  translation  of  the  third  edi- 
tion all  cases  of  fission  are  included  under  the  Formation  of  Cells  by 
Division  of  the  Mother-Cell. 


BOTANY. 


the  wliolf  of  the  protoplasm  of  the  mother-cell  is  used.     The  former  he 

calls  Free  Cell  Formation ,  and 
the  latter  Formation  of  Cells 
by  Division  of  tlie  Mother- 
Cell,  and  includes  also  under 
the  last  a  part  of  what  has 
been  described  above  under 
the  head  of  Fission.  It  is 
doubtful,  however,  whether 
such  a  division  is  of  much 
importance. 

(&)  What  has  been  called 
the  Rejuvenescence  of  a  cell 
may  be  mentioned  here.  The 
phenomena  connected  with  it 
are  as  follows:  The  proto- 
plasm of  a  cell  contracts,  ex- 
pels a  portion  of  the  water 
contained  in  it,  and  escapes 
through  a  slit  in  its  wall  ;  the 
naked  mass  becomes  for  a 
time  a  free-swimming  zoos- 
pore,  after  which  it  secretes  a 
wall  of  cellulose,  and  begins 
to  grow  and  form  new  cells 
by  fission.  Cases  of  this  kind 
occur  in  CE/tloffonium,  Stigeo- 
clonium,  and  many  other 
aquatic  Thallophytes.  An 
interesting  fact,  but  proba- 
bly of  no  great  significance, 
is  that  the  axis  of  growth  of 
the  new  cell  is  perpendicular 
to  that  of  the  old  one. 

While  there  can  be  no  doubt 
that  this  process,  as  Sachs 

Fig.S8.-/totoi«n««wtfa.  A,  vertical  section  insists*  "must  be  regarded 
of  i he  whole  plant;  h,  hymenium  -i.e..  the  layer  morphologically  as  the  for- 
ihwhirh  the  spore-forming  sacs  lie  ,  <S.  the  tissue  ..  ,  "  ,,  „  ., 

of  the  fungus  envelop'ng  the  hymenium  at  its  Cation  of  a  new  cell,  there 
edge  q  in  a  cup  like  manner  ;  at  the  base  of  the  can  be  little  question  that  it 
tissue  5  fine  threads  arise,  which  grow  between  .  ,  . 

the  particles  of  earth.    /?,  H  small  portion  of  the  "» closely  related  to  the  forma- 

tle^'ovc^]»raems'(li3vnha!\!'-1  <i  toV^ore  form  lion  °f  ZOO9Porc8  described 
lag  Me>  (<M^  With  ^£ofll«iMnta(pai«phyM«)  above  (p.  40).  The  differ- 
between  them.  A  X  20,  B  X  650,-After  Sachs.  ence  ig  that  in  tbe  formation 

of  ordinary   zoospores  the   mother-cell   breaks   up    into    more    than 

*  See  "Text-Book,"  p.  9,  and  also  "Lehrbuch,"  4te  Auf.,  where  the 
author  sets  apart  tliiaaa  an  entirely  different  mode  of  cell-formation. 


CELL  FORMATION  BY  DIVISION. 


4..'! 


one  mass  before  escaping  ;  while   in  Rejuvenescence  the  whole  proto- 
plasm escapes  without  dividing.     Rej  uvenescence  may  then  be  regarded 


Fi2.  33.— Endosperm-cells  of  Phaseolus  multiflorus.  A,  the  production  of  new  cells 
in  the  protoplasm  of  the  embryo  sac  ;  n,  n,  n,  nuclei ;  a,  a,  a,  masses  of  protoplasm 
gathered  around  the  nuclei  ;  b,  young  cell,  but  without  a  wall  of  cellulose  ;  c,  young 
cell  with  a  wall ;  c',  d,  young  cells  with  walls  and  vacnoles.  B,  two  cells  of  the 
endosperm  in  a  much  later  stare  ;  the  cells  have  fused  their  walls  so  as  to  form  a 
false  tissue  ;  in  the  angles  between  the  cells  are  intercellular  cpac^s  filled  with  some 
of  the  protoplasm  of  the  mother-cell  (embryo  sac)  ;  the  cell  n  is  in  process  of  fission, 
the  two  nuclei  n,  n,  are  near  together,  as  if  formed  by  the  flss'on  of  the  original  nu- 
cleus ;  ,«,  line  indicating  the  boundaries  of  the  two  masses  of  pn.toplasm;  the  cell 
b  \*  fully  divided,  and  the  two  parts  are  sep  irated  by  the  wall  cl.  X  670.— After 
Dippel. 

as  a  case  of  internal  cell-formation  in  which  there  ia  no  division  of  the 
protoplasm. 


BOTANY. 


56.—  Cell-Formation  by  Union.  The  simplest  example 
of  cell-formation  by  the  union  of  cells  is  found  in  the  Myx- 
omycetes.  The  swarm  -spores  which  have  been  described  as 
multiplying  by  division  (see  p.  36)  somewhat  later  begin 
the  opposite  process  of  uniting.  Two  or 
more  approach  one  another  and  gradually 
coalesce  into  a  homogeneous  protoplasmic 
mass  (Fig.  34).  During  the  process  the 
nuclei  disappear.  The  union,  at  first 
sight,  appears  to  be  no  more  than  a  mere 
running  together  of  similar  drops;  but  the 
disappearance  of  the  nuclei  shows  that, 
Fig.  34.-  Union  (the  however  much  it  may  resemble  such  a 
of  "the  swarm'-epores'of  purely  physical  process,  the  coalescing  of 
the  swarm-spores  of  the  Myxomycetes  is 
!  something  more.  It  is  possible  that  there 
fue°ed  Into  one^c  th™I  ^8  also  some  very  s^g^fc  difference  between 


afterward,  the  two  up- 
per  ones  fused  into  onv. 


57.  —  In     Cl>H)ll(iniun,    a 


of     the 


gCHUS 
v.     _  ..  ...  ,,      ,  ., 

390.—  After  cienkow-  Desmidiaceae,  the  uniting  cells  have  well- 
developed  walls,  and  as  a  consequence  the 
process  is  somewhat  different  from  what  it  is  in  the  Myxo- 
mycetes. The  cells,  which  in  this  genus  are  two-lobed  (Fig. 
35),  approach  each  other  ;  each  sends  out  from  its  centre  a 
protuberance  which  meets  the  other  (d)  ;  the  thin  walls 
separating  the  cavities  of  the  protuberances  are  absorbed,  and 


Fig.  35.— Cosmarivm  MeneyMnil.  a,  b,  c,  different  views  of  the  mature  plant"  ; 
d,  e,  and/,  three  stages  in  the  formation  of  the  new  cell  ;  gji,  and  i,thc  ufter-di-vt-l- 
opment  of  the  new  cell.  X  475.  —  After  CErstcd. 

the  united  protoplasmic  masses  form  a  round  ball  (e),  which 
soon  becomes  enclosed  in  its  own  proper  coatings  (/). 

58. — The  union  of  cells  in  SpirOffyra  is  much  like  11, at  of 
Cosmarinm.     Here  the  cells  arc1  united  into  long  filaments, 


CELL  FORMATION  BT  UNION.  45 

instead  of  being  independent,  as  in  the  previous  case.  At 
the  time  of  union  the  filaments  approach  one  another  and  lie 
nearly  parallel ;  protuberances  grow  out  from  the  contiguous 
cells  (Fig.  36,  a,  b)  ;  their  extremities  meet,  and  the  walls  are 
absorbed,  making  a  channel  of  communication  from  cell  to 
cell  (Fig.  36).  Through  this  channel  the  protoplasm  from 
one  of  the  cells  passes  into  the  cav- 
ity of  the  other ;  the  two  masses 
unite  and  form  a  round  or  ovoid 
cell,  which  soon  secretes  a  wall  of 
cellulose  (Fig.  37,  A,  b,  and  B,  c). 

The  particular  kind  of  union  in  which 
the  two  cells  are  of  equal  or  nearly 
equal  size,  and  illustrated  above  by  Cos- 
marium  and  Kpirogyra,  has  received  the 
name  of  Conjugation.  It  is  character- 
istic of  one  group  of  the  Thallophytes, 
viz.,  the  Zygosporece. 

59. — In  Vaucheria,  a  fresh-wa- 
ter Thallophyte,  we  have  an  ex- 
ample of  the  union  of  cells  of  very 
different  sizes.  The  larger  cells 
(called  oosplieres)  are  in  lateral 
protuberances  of  the  large  single 
cell  which  composes  the  whole 
plant  (Fig.  38,  A,  and  B,  og).  The 
protoplasm  in  these  is  of  a  spheri- 
cal form,  and  is  much  denser  than 
in  the  main  cell,  from  which  it  is 
separated  in  each  case  by  a  trans- 
verse Wall  (shown  in  F\  The  Fig-  36.—  Two  filaments  of  Spiro- 
,>  >,.  ,  .  7X  gyra  longata  about  to  conjugate ; 

Smaller    cells    (the    SperinatOZOiaS)     at  a  and  &  are  seen  the  protuber- 
,         a   v     j.v     •    A  i       11       ances  from  the  contiguous  cells 

are  produced  by  the  internal  cell-  approaching  each  other,  xsso.- 
division  of  the  protoplasm  of  simi-  Aft€ 
lar  protuberances  (the  antheridia,  A,  and  B,  a).  They  are 
very  small  as  compared  with  the  oospheres,  and  are  naked 
masses  of  protoplasm  provided  with  two  cilia,  by  means  of 
which  they  are  locomotive  (D).  Upon  escaping  into  the 
water  by  the  bursting  of  the  old  wall,  they  swim  about,  and 


46 


BOTANY. 


some  of  them  finally  reach  the  oosphere  (through  a  rupture 
in  its  wall),  and  unite  with  its  protoplasm  (E,  F).  The  re- 
sult is  at  once  seen  in  its  greater  sharpness  of  outline,  and 
in  the  development  of  a  cell-wall,  whereby  the  oosphere  is 
transformed  into  an  oospore. 

60.  —Essentially  the  same  kind  of  union  takes  place  in  the 
nearly  related  parasitic  group,  the  Peronosporece.  The  only 
difference  is  that  here  the  antheridium  (Fig.  39,  n)  comes  in 
direct  contact  with  the  oosphere  (o)  by  means  of  a  project- 
ing tube,  and  through  this  tube  the  protoplasm  masses  of 

the  two  cells  unite. 
The  absence  of  mo- 
tile spermatozoids 
in  this  case  is  prob- 
ably connected  with 
the  fact  that  these 
plants  live  in  the 
tissues  of  land 
plants,  instead  of 
being  immersed  in 
water. 

61.— The  first  cell 
of  the  embryo  in 
mosses  is  the  result 
of  li  union  of  cells 


Pig.  37. -Filaments  of 
the  protoplasm  is  passing  from  the  lower  < 
per  ;  at  6  the  union  of  tEe  two  protoplasmic  masses  is    rlifferinff   PTesitlv    in 
completed ;  in  B  the  protoplasmic  ma»e«  have  se-    C 

crered  thick  walls,  thus  completing  the  formation  of    size.          The     1;U'°"(T 
the  new  cells.     X  550.— After  bachs.  . 

cell  lies  at  the  bot- 
tom of  a  flask-shaped  organ,  the  archegonium  (Fig.  40,  B, 
b)  ;  the  smaller,  the  spermatozoids,  are  developed  by  the  in- 
ternal cell-division  of  another  organ,  the  antheridium  (Fig. 
41,  -4).  The  spermatozoids,  as  in  Vaucheria,  are  nakod 
masses  of  protoplasm,  provided  with  cilia,  by  means  of 
which  they  swim  freely  through  the  water  (Fig.  41,  B}. 
Upon  coming  in  contact  with  the  large  cell  in  the  archego- 
nium they  fuse  with  it,  and  thus  make  a  new  cell. 

62. — In  Phanerogams  the  first  cell  of  the  embryo  is  the  re- 
sult of  the  union  of  the  protoplasm  contained  in  the  pollen- 
cell  with  that  in  the  embryo  sac.  Here  again  the  two 


CELL  FORMATION  BY  UNION. 


masses  come  in  direct  contact  by  means  of  a  tube  (the  pol- 
len tube)  which  touches  with  its  lower  extremity  the  embry- 
onic vesicle. 

(a)  The  foregoing  classification  of  the  modes  of  cell -formation  differs 
in  many  respects  Irom  that  given  by  Sachs  in  the  fourth  edition  of  his 
"  Lehrbuch."  His  classification  as  there  given  is  as  follows  : 


. 


Fig.  3S.  —  Vtiucheria  sessilis.  A,  origin  of  the  lateral  branches,  on  (mgnnhm),  and 
h  (anttifridium),  from  the  filament  ;  B,  the  branch  a  (the  same  as  h  in  A)  has  its  ter- 
minal portion  cut  off  by  a  partition  ;  in  ng  the  protoplasm  is  becoming  greatly  con- 
densed ;  C.  the  same  as  o<i  of  B.  but  further  advanre-1  (now  called  an  oosphere)  and 
the  wall  burst  open,  permitting  the  escape  of  a  drop  of  mucilage  si ;  1),  small  motile 
cells  (sprrinatozoids)  from  the  terminal  cell  of  a  in  li  ;  E,  the  samo  as  C,  but  a  little 
later— the  spermatozoids  are  entering  through  the  opening  ;  F.  a,  the  branch  a  in  B, 
with  the  terminal  cell  now  empty,  on  account  of  the  escape  of  the  gpermntozoids  ; 
o*p,  the  same  as  E,  and  og  in  B,  after  union  with  tho  spermatozoids — the  protoplasm 
is  surrounded  by  a  tbick  cell-wall  and  it  is  now  called  an  oospore.  X  100. — After 
Sachs. 

A.— FORMATION  OP  REPRODUCTIVE  CELLS. 

1.  Rejuvenescence. 

2.  Conjugation. 

3.  Free  Cell-Formation. 

4.  Formation  of  Reproductive  Cells  by  Division,  which  is  made  to 
include  the  formation  of  pollen,  the  spores  of  mosses  and  frrns,  and 
the  conidia,  stylospores,  and  basidiospores  of  many  fungi. 


48 


BOTANY. 


Fig.  3Q.—Peronospora  alstnenrum.  A ,  yonng  oosconinm  o,  and  young  antheridium 
n,  in  contact  with  it ;  B,  the  antheridium  u  beginning  to  pierce  the  oogonium  o,  whose 
protoplasm  is  becoming  condensed  ;  C",  the  fine  tube  of  the  antheridium  n  has  pen- 
etrated the  oogonium  o,  and  come  in  contact  with  its  condensed  and  rounded  proto- 
plasm, the  oof-ptere.  X  350.— After  De  Bury. 


Fia.  40. 


Fig.  40. — Female  reproductive  organs  of  a  moss,  Funaria  hygrometrica.  A,  apex 
of  tfie  stem  ;  a,  archegonia  ;  b,  leavi  s :  B,  archegonium  ;  o,  base  :  h,  neck  ;  TO, 
mouth  :  C,  month  of  fertilized  archegonium  A  x  100,  B  X  550.— After  Sachs. 

Fig.  41. — Male  reproductive  organs  of  tht>  same  moss.  A^  antheridium  open  and 
permitting  the  ppermatozoids  a  to  escape  ;  //.  It.  spe;  ni-cell  of  another  moss  (Polytri- 
chum),  with  contained  ppermatozoid ;  c,  .-pormatozoid  free,  with  two  cilia  at  the 
pointed  extiemity.  A  X  850,  B  X  800.— After  Sucha. 


CELL  FORMATION  BY   UNION.  49 

B. — FORMATION  OF  VEGETATIVE  CELLS. 

1.  By  the  progressive  formation  of  a  division  wall. 

2.  By  the  simultaneous  formation  of  a  division  wall. 

The  main  objection  to  this  classification   is  that  its  principal  divis- 
ions are  based  upon  physiological  distinctions  alone. 

(6)  Duchartre,  in  his  "  Elements  de  Botanique,"  makes  a  very  sim- 
ple classification,  as  follows  : 

A.— FREE  CELL-FORMATION. 

1.  Intracellular. 

2.  Extracellular  [Rejuvenescence]. 

B. — FORMATION  OF  CELLS  BY  DIVISION. 

1.  Progressive  division. 

2.  Simultaneous  division. 


Note  on  Paragraph  56.  "  From  the  researches  of  Schmitz  on  the 
Myxomycetes  (Sitzber.  d.  uieder-rhein.  Ges.  in  Bonn,  1879),  it  appears 
that  the  nuclei  of  the  cells  which  coalesce  to  form  the  plaemodium  do 
not  fuse,  but  remain  distinct :  this  case  of  coalescence  of  cells  cannot, 
therefore,  be  any  longer  regarded  as  an  instance  of  cell-formation  by 
conjugation."  (8.  H.  Vines  in  Apn.  to  Sachs'  Text-Book  of  Botany. 
Second  English  Edition,  p.  945.) 


CHAPTER  V. 

PRODUCTS   OF   THE   CELL. 

§  I.  CHLOROPHYLL. 

63. — In  many  plant-cells  definite  portions  of  the  proto- 
plasm have  a  green  color,  on  account  of  the  presence  of  a 
peculiar  chemical  compound  known  as  Chlorophyll.*  The 
protoplasmic  bodies  thus  colored  are  called  chlorophyll-bod- 
ies, or  chlorophyll  granules,  while  to  the  coloring-matter 
alone,  distributed  in  small  quantity  through  their  substance, 
the  name  chlorophyll  is  properly  applied. 

64. — The  chlorophyll-bodies  are  of  various  shapes  and 
sizes.  In  some  of  the  lower  plants  nearly  the  whole  of  the 
protoplasm  is  colored,  giving  the  whole  cell  a  uniform  green 
color.  In  others  there  are  stellate  or  band-like  chlorophyll- 
bodies  distinct  from  the  mass  of  the  protoplasm  of  the  cell  ; 
the  band-like  bodies  are  straight,  or  more  commonly  spiral 
(Fig.  42).  In  the  great  majority  of  cases,  however,  the 
chlorophyll-bodies  are  simple  rounded  granules  of  such  mi- 
nute size  that  many  are  contained  in  a  single  cell  (Fig.  43). 
The  chlorophyll  may  be  dissolved  out  of  its  protoplasmic 
vehicles,  leaving  the  latter  with  the  appearance  and  chemi- 
cal properties  of  ordinary  protoplasm. 

65. — The  exact  chemical  composition  of  chlorophyll  is  not 
known.  As  obtained  by  the  evaporation  of  its  alcoholic 
solution  it  is  a  green  resin-like  powder,  insoluble  in  water. 
From  the  partial  analyses  of  Kromayer  it  is  probable  that  it 
contains  carbon,  hydrogen,  nitrogen,  and  oxygen,  and  there 
are  good  reasons  for  believing  that  iron  is  also  one  of  its  con- 
stituents. 


*  Chlorophyll  is  also  found  to  a  limited  extent  in  the  animal   king- 
dom.    It  is  present,  for  example,  in  Euglena  and  Hydra. 


CHLOROPHYLL. 


51 


66. — With  few  exceptions  chlorophyll  is  not  found  in  cells 
which  are  not  exposed  to  the  action  of  light.*  When  ordi- 
nary green  plants  are  removed  for  some  time  from  the  light, 
the  chlorophyll  disappears  from  the  chlorophyll-bodies,  and 
leaves  them  colorless.  The  same  decoloration  also  takes 
place  when  a  plant  is  deprived  of 
iron  as  one  of  the  constituents  of 
its  food.  The  disappearance  of 
chlorophyll  takes  place  normally  in 
higher  plants  when  the  cells  lose 
their  activity.  In  the  case  of  leaf- 
cells,  upon  the  approach  of  autumn 
the  chlorophyll  appears  to  be  re- 
moved to  other  portions  of  the 
plant. 

(a)  The  cells  of  many  Palmellacere, 
and  many  swarm-spores — e.g.,  of  (Edogo- 
nium  and  Vaucheria — furnish  good  ex- 
amples of  the  coloration  of  nearly  the 
whole  body  of  protoplasm. 

In  Zygnema  th'j  chlorophyll-bodies  are 

stellatu,  and  in  Spiroyyr,',  spiral. 
In  Vaucheria  there  are  multitudes  of 

roundish  or  slightly  angular  clilorophyll- 

bodies,  which  line  the   interior  of  the 

large    cells.      The   chlorophyll    in    the 

leaves  of  many  mosses  may   be    easily 

studied,  even  without  making-  sections  ; 

in  them  the  chlorophyll-bodies  are  round- 
ish in  outline.    In  the  higher  plants  thin 

cross-sections   of  the   leaves   afford   the 

best  means  for  the  examination  of  their     pjg  43.— Two  filaments  of  Spl- 

longata  ;  the  chlorophyll 
iral  bands  ;  in  the  centre 
.  cell  is  a  nucleus,  with 

(b)  Chlorophyll  is  soluble   in  alcohol,   x^^VtSch?'  protoplasm- 
ether,  chloroform,  benzine,  essential  and 

fatty  oils,  hydrochloric  and  sulphuric  acids,  and  these  may  be  used 

*  The  cotyledons  of  many  Coniferae  acquire  a  green  color  even  in 
total  darkness.  The  embryo  of  Phoradendron  is  green  in  the  unopened 
seed,  and  in  certain  seeds  with  thick  coats,  which  are  impervious  to 
light  (e.  g.,  in  some  (Jucurbitdceae),  a  chlorophyll -bearing  layer  of  cells 
surrounds  the  embryo. 


chlorophyll-bodies,  which  are  uniformly  ro,jyra  longata :  the  chlorophyll 

...  ,    ,         ..  is  in  epiral  bands ;  111  the  centre 

of  a  simple  rounded  outline.  of  eacu  ceii   \6  a  nucleus,  with 


BOTANY. 


for  obtaining  solutions.    In  transmitted  light  the  alcoholic  solution  is 

green,  but  when  viewed  by  reflected  light  it  apjiears  to  be  red. 

When  an  alcoholic  solution  of  chlorophyll  is  boiled  for  a  few  minutes 

with  an  alcoholic  solution  of  potash, and  then  neutralized  with  hydrochlo- 
ric acid  two  substances  are  ob- 
tained :  the  one  as  a  yellow  pre- 
cipitate, named  Pltylloxaitthinc, 
and  the  other  a  blue  substance 
dissolved  in  the  supernatant 
liquid  ;  by  evaporation  the  lat- 
ter may  be  obtained  as  a  blue 
powder,  named  PJiyllocyanine. 
(e)  The  importance  of  iron  in 
giving  a  green  color  to  plants 
is  easily  demonstrated  by  grow- 
ing young  plants  of  Indian  corn 
in  solutions  containing  no  iron. 
The  first-formed  leaves  are 
green,  but  subsequently  only 
colorless  ones  are  produced ; 
alter  the  addition  of  iron  in  the 
form  of  fen  ic  sulphate  or  ferric 
chloride,  the  colorless  leaves 
become  green  in  the  course  of 
a  few  days. 

The  importance  of  light  in 
the  production  of  chlorophyll  is 
shown  in  the  etiolated  shoots  of 
the  potato  when  grown  in  a 
dark  cellar ;  the  same  thing 
may  be  shown  by  germinating 
the  seeds  of  many  common 
plants  in  dark  boxes. 

(d)  The  disappearance  of  chlo- 
rophyll is  seen  in  the  common 
43  -Chlorophyll  grannies  in  cells  of  operation    of   blanching   celery 

the  leaf  of  a  moss,  Funana  fnjf/rometrica.  A,  for  table  use,  and  in  the  blanch- 

granules  of  chlorophyll  with  contained  starch 

grains,  embedded  in  the  protoplasm  of  the  nig      of      grass -blades     under 


b",  granules  dividing;   c,  d,  ami  e,  old  gran-  ing  such  colorless  plants  to  the 
tefOaFStt  la&S^  ljeht  chlorophyll  is  produced, 
of  chlorophyll  gnmule  hy  the  action  of  water.      (e)  Many  plants  which  contain 

chlorophyll    have   their   green 

color  hidden  by  the  presence  of  some  other  coloring-matter.  Some- 
times this  is  dissolved  in  the  water  contained  in  the  vacuoles  ;  this  ia 
the  case  in  Coleus,  in  which  the  dissolved  pigment  is  red.  In  young 
plants  of  Atriplex  the  epidermal  cells  are  filled  with  such  a  red  solu- 
tion, hiding  the  green  chlorophyll-bearing  cells  underneath.  In  cer- 


STARCH.  53 

tain  algae  the  chlorophyll-body  itself  contains  other  coloring-matters — 
soluble  in  water,  however — in  addition  to  the  chlorophyll.  Iti  Floridece, 
(red  sea-weeds)  this  extra  coloring-matter  is  red  ;  in  Fucacew,  brown  ; 
in  Diatomacea,  yellowish  ;  and  iu  Oscillaloriw,  blue. 

In  the  degradation  of  chlorophyll,  which  takes  place  in  the  walls  of 
the  antheridia  of  mosses,  and  in  the  ripening  of  some  fruitsof  Phanero- 
gams, other  colors  than  gre^n  are  produced. 

(/)  Plants  which  live  parasitical ly  upon  others,  as  the  Dodder,  and 
those  which  are  saprophytic  in  habit,  as  some  fungi,  are  usually  desti- 
tute of  chlorophyll ;  where  the  parasitism  is  only  partial,  as  in  CastUlei'i 
and  Oerardia,  or  where  the  food  used  (stolen)  by  the  parasite  is  unas- 
similated,as  in  the  Mistletoe,  chlorophyll  is  present.  In  the  true  sapro- 
phytes (found  mainly  among  the  fungi)  chlorophyll  is  never  present. 

(g)  The  colors  of  flowers  are  produced  in  various  ways.  In  some 
cases  rounded  masses,  apparently  protoplasmic  in  their  nature,  contain 
a  red  (e.g.,  Adonis),  orange  (e.g. ,  Zinnia),  or  yellow  (e.g. ,  Cucurbita)  color- 
ing-matter. In  other  cases  the  pigment  is  dissolved  iu  the  watery  fluid 
of  the  cells  ;  blue  and  violet  colors  are  mostly  produced  in  this  way. 
White  petals  are  so  because  their  external  layers  of  cells  are  fillel 
with  air.  An  important  difference  beween  chlorophyll  and  the  pigments 
of  flowers,  is  that  the  latter  appear  not  to  be  dependent  upon  light  for 
their  production  ;  this  may  be  shown  by  enclosing  branches  of  morning- 
glory  (lpom<KO)  bearing  young  flower-buds  in  a  dark  chamber  ;  when 
the  flowers  expand  they  will  be  seen  to  have  their  natural  colors. 


§11.   STARCH. 

67. — Next  to  chlorophyll,  one  of  the  most  important  pro- 
ducts of  the  plant-cell  is  starch,  an  organic  compound  closely 
related  to  sugar  and  cellulose,  and  represented  by  the  em- 
pirical formula  Cia  Hao  010.  It  occurs  in  the  form  of  whitish 
or  semi-transparent,  rounded  or  slightly  angular  stratified 
grains,  and  is  generally  found  closely  packed  in  the  interior 
of  certain  cells. 

68. — The  form  of  starch  grains  varies  greatly  in  different 
plants,  and  considerably  even  in  the  same  plants  ;  neverthe- 
less, the  general  appearance  of  the  grains  in  each  plant  is  so 
characteristic  that  the  different  kinds  of  starch  may  be  quite 
easily  distinguished.  In  every  case  the  grains  have  more  or 
less  clearly  defined  lines,  which  are  concentrically  arranged 
about  a  nucleus  *  (Figs.  44  and  45).  In  some  cases  (excep- 

*  The  nucleus  is  called  the  hilitm  by  some  authors,  a  term  which 


54 


BOTANY. 


tionally  in  some  plants  and  uniformly  in  others)  two  or  more 
nuclei  occur  in  each  grain  ;  by  growth  such  grains  become 
compound  and  may  finally  separate  into  as  many  parts  as 
there  are  nuclei. 

69. — The  molecular  structure  of  the  starch  grain  has  been 
determined  to  be  similar  to  that  of  plant-cellulose.  It  is  re- 
garded as  composed  of  molecules,  each  of  which  is  surrounded 
by  a  watery  layer  of  greater  or  less  thickness.  Growth  takes 
place  by  the  intercalation  of  new  molecules  between  the  pre- 
viously formed  ones — in  other  words,  by  intussusception, 

exactly  as  in  the  case  of 
the  cell-wall.  During  Ihe 
formation  of  the  grain,  in 
certain  portions  of  it  the 
watery  layers  surrounding 
the  molecules  become 
thicker.  When  seen  by 
a  transmitted  light  such 
more  watery  parts  appear 
darker  than  those  which 
are  less  watery,  and  an  ex- 
amination shows  that  they 
surround  the  nucleus  on 
all  sides  in  a  concentric 
manner.  In  this  way  the 
starch  grain  comes  to  be 

and  concentric  striae;  a,  grannleB  of  aleu,  one;  made  UP  °f  alternating 
M,  intercellular  spaces.  X  800.-AfUr  Sachs,  lavers  of  more  and  less 

watery  substance.  Every  watery  layer  is  thus  between  two 
layers  which  contain  less  water,  and  so  every  less  watery  one 
lies  between  two  more  watery  ones.  As  an  increase  in  the 
amount  of  water  in  any  portion  of  the  starch  grain  de- 
creases the  density  of  that  portion,  the  layers  just  described 
may  be  distinguished  as  of  greater  density  when  having 
less  water  and  of  less  density  when  having  more  water. 


Fig.  44.-  Cell*  from  the  cotyledon  of  the  pea, 
(Pigum  satimnn).  St,  t-tarch  grains  with  nucleus 


should  be  abandoned,  as  it  was  originally  given  under  the  mistaken 
notion  that  it  was  the  point  of  attachment  of  the  starch  grain  while 
growing. 


STARCH. 


70. — There  are  two  kinds  of  starch  in  every  starch  grain. 
The  great  mass  is  made  up  of  a  more  readily  soluble  form, 
the  granulose,  while  the  remainder,  amounting  to  not  more 
than  from  two  to  six  per  cent  of  the  whole  grain,  is  less  solu- 
ble, and  boars  some  resemblance  to  cellulose ;  it  is  distin- 
guished as  starch-cellulose.  These  two  forms  are  intimately 
combined  throughout  the  whole  starch  grain,  so  that  upon 
the  removal  of  the  granulose  by  solution  a  perfect  skel- 
eton of  the  grain  still  re- 
mains. 

71.— The  first  forma- 
tion of  starch  appears  to 
take  place  in  the  chloro- 
phyll-bodies when  they 
are  exposed  to  the  light 
(Fig.  43,  B,  p.  52,  and 
Fig.  36,  p.  45).  The 
grains  thus  formed  are 
extremely  minute,  and  of 
different  shapes  and  sizes 
in  each  chlorophyll-body ; 
they  do  not  remain  and 
grow  into  larger  grains, 
but  are  dissolved  upon 
the  withdrawal  of  light. 
Thus  the  starch  formed 
during  the  day  disappears 

during  the    night    and    is  thmpJates  of  protoplasm.    In  the  figures  a  to  g, 
,°  the  starch  grains,  taken  from  a  germinating  In. 

doilbtleSS  Carried   to  Other  dian  corn  grain,  lire  becoming  dissolved  and 
disintegrated.    X  800.— After  Sachs. 

portions  of  the  plant. 

72. — The  formation  of  ordinary  starch  grains  always  takes 
place  in  protoplasm  ;  in  fact,  they  may  be  said  to  be  secre- 
tions from  the  protoplasm,  just  as  cellulose  is  said  to  be  a 
secretion.  In  a  cell  whose  cavity  is  filled  with  full-grown 
starch  grains  the  protoplasm  has  almost  entirely  disappeared, 
only  small  portions  of  it  remaining  as  thin  plates  or  scales 
between  the  grains  (Fig.  45). 

(a)  Starch  occurs  in  nearly  all  chlorophyll-bearing  plants  ;  it  is  absent 
only  in  Nostociicece,  Oscillatoriie,  and  other  algae  whose  chlorophyll. 


56  BOTANY. 

bodies  contain  an  additional  blue  pigment.  It  is  present  in  many 
plants  which  are  destitute  of  chlorophyll  ;  this  is  the  case  with  the 
parasitic  Phanerogams  ;  it  occurs,  for  example,  in  the  stem  of  Cuscula, 
and  in  the  underground  portions  of  Orobanche  and  Lathrcea.  From 
chlorophyll-less  Thallophytes  (fungi),  with  rare  exceptions,  it  appears  to 
be  absent.* 

(&)  The  best  common  examples  for  the  study  of  fully  formed  starch 
grains  are  the  following,  viz.,  tubers  of  the  potato,  seeds  of  the  bean 
and  pea,  grains  of  wheat,  Indian  corn,  rice,  etc.  Oat-starch  and  that 
of  the  crocus  corni  exist  in  the  form  of  compound  grains.  Of  those 
named,  the  starch  grains  of  the  potato  and  the  bean  are  the  largest, 
being  about  .07  mm.  (.003  inches)  in  diameter,  while  those  of  rice  are 
the  smallest,  being  about  .007  mm.  (.0003  inches)  in  diameter. 

(c)  Thetest  which  is  characteristic  of  starch  is  its  blue  coloration  when 
treated  with  a  weak  solution  of  iodine.     When  the  solution  is  strong 
the  color  is  so  intense  as  to  appear  black.     A  careful  examination  shows 
that  it  is  only  the  granulose  which  is  thus  colored  blue  by  iodine, 
but  on  account  of  its  much  greater  quantity  and  its  intimate  mixture 
with  the  starch-cellulose,   the  blue  granulose  gives  its  color  to  the 
whole  grain. 

(d)  An  indication  of  the  correctness  of  the  present  view  as  to  the 
structure,  of  the  starch  grain  and  the  cause  of  si  ratification  may  be 
obtained  in  two  ways,  as  follows:  1st,  by  thoroughly  drying  the  grain 
by  evaporation  of  its  water  or  by  placing  it  in  absolute  alcohol;  all 
parts  having  now  equal  amounts  of  water,  the  striae  disappear;  3d,  by 
rendering  all  parts  of  the  grain  capable  of  absorbing  large  quantities 
of  water,  as  may  be  done  by  means  of  a  weak  solution  of  potash,  as  in 
this  way   the  difference  in   the   amount  of  water  in  different  layers 
being  destroyed,  the  stria3  disappear  as  before. 

The  drying  process  just  referred  to  reveals  another  structural  pecu- 
liarity, viz.,  that  the  interior  portions  of  the  starch  grain  contain  the 
greatest  amount  of  water.  On  drying,  internal  fissures  appear,  radiating 
from  a  central  cavity  and  having  a  narrower  diameter  as  they  pass  out- 
ward, showing  that  the  loss  of  water  is  greatest  in  the  interior. 

(e)  The  separation  of  the  granulose  from  the  starch-cellulose  may  be 
accomplished  in  the  following  ways :  (1)  by  allowing  the  starch  grains  to 
remain  for  a  long  time  in  a  weak  solution  of  hydrochloric  or  sulphuric 
acid  ;  the  acid  solution  must  not  be  strong  enough  to  cause  the  grains 
to  swell  ;  (2)  by  the  action  of  saliva  at  a  temperature  of  40°  to  47°  C. 
(105°  to  117°  Fahr.).     In  either  case  the  granulose  is  removed  and  the 
starch  cellulose  remains  as  a  skeleton.     Upon  treatment  with  a  solu- 
tion of  iodine  the  skeleton  is  colored  brown  instead  of  blue.     Other 

*  Hofmeieter,  in  "  Lelire  von  der  Pflanzenzelle,"  from  which  the 
preceding  statements  have  been  mainly  taken,  states  that  starch  gran 
ules  occur  in  the  oospores  of  Saprolegniee. 


ALEURONE  AND  CRYSTALLOIDS.  5? 

agents,  as  organic  acids,  diastase,  and  pepsin,  also  are  solvents  of 
granulose. 

(/)  The  natural  solution  of  starch  grains  takes  place  in  the  cells  of 
living  plants  in  a  way  somewhat  similar  to  the  artificial  removal  of 
granulose.  The  process  is  not,  however,  so  regular  and  uniform ; 
holes  and  irregular  excavations  are  formed  in  the  grains,  sometimes 
with  the  removal  of  the  granulose  only,  and  in  other  cases  with  the 
solution  of  the  whole  substance  ;  sooner  or  later  the  grains  break  up 
into  pieces,  and  by  a  continuation  of  the  process  of  solution  they  soon 
disappear  (Fig.  45,  a,  g).  Sachs  maintains  that  starch  may  thus  be 
dissolved  in  the  cotyledons  of  the  bean  and  transferred  to  other  parts 
of  the  plantlet,  reappearing  in  the  form  of  grains  without  undergoing 
chemical  change  or  conversion  into  sugar. 

(g)  Observations  upon  the  formation  and  disappearance  of  starch 
grains  in  the  chlorophyll-bodies  are  best  made  with  Spirogyra.  By 
keeping  healthy  filaments  of  this  plant  in  darkness  for  some  time  the 
starch  disappears ;  upon  exposure  to  direct  sunlight  the  formation  of 
starch  begins  again  in  about  two  hours;  in  diffused  daylight  it  begins 
several  hours  later.  Other  plants  with  thin  tissues  may  also  be  used, 
as,  for  exainple,  the  thin  leaves  of  mosses,  etc. 

(h)  The  development  and  growth  of  starch  grains  may  be  studied  in 
the  ripening  grains  of  Indian  corn,  by  making  extremely  thin  sec- 
tions at  different  stages  of  the  ripening  process.  They  always  appear 
at  first  as  minute  solid  globular  masses  in  the  protoplasm. 

§  III.  ALEURONE  AND  CRYSTALLOIDS. 

73. — In  the  ripening  of  seeds  and  the  maturation  of  tubers 
the  loss  of  water  by  the  protoplasm  gives  rise  to  a  number  of 
poorly  understood  forms  of  albuminous  matter.  Two  of  the 
most  noteworthy  of  these  are  Aleurone,  and  the  crystal-like 
bodies  known  as  Crystalloids. 

74. — Aleurone  occurs  in  the  form  of  small  rounded 
grains,  sometimes  occupying  a  great  portion  of  the  cavity  of 
the  cell  (Fig.  44,  a,  p.  54).  They  are  soluble  in  water,*  or 
in  water  containing  a  little  potash  ;  but  are  insoluble  in  alco- 
hol, ether,  benzole,  or  chloroform.  They  frequently  contain 
other  bodies  enclosed  in  their  substance,  as  crystalloids  (de- 
scribed below),  globoids  (composed  of  a  double  calcium  and 
magnesium  phosphate),  and  crystals  of  calcium  oxalate. 

*  The  aleurone  grains  of  Cynoglossum,  officinale  are  stated  by  Sachs 
not  to  be  soluble  in  water. 


58  BOTANY. 

75. — Aleurone  grains  appear  in  seeds  during  the  last 
stages  of  ripening.  In  the  turbid  cell-contents,  as  the  loss 
of  water  proceeds  small  globular  masses  of  albuminous  mat- 
ter appear,  and  afterward  increase  their  size ;  by  the  con- 
tinued loss  of  water  they  become  harder  and  of  a  more  defi- 
nite outline.  In  the  germination  of  the  seed  the  aleurone 
grains  dissolve,  and  the  protoplasmic  contents  of  the  cells 
assume  very  nearly  the  condition  they  held  before  the  final 
changes  in  the  seed  which  produced  the  aleurone. 

Aleurone  may  be  studied  in  the  seeds  of  tbe  bean,  pea,  vetch,  and 
lupine,  and  in  acorns,  chestnuts,  horsechestnuts,  and  tbe  bran-cells  of 
the  oat-grain. 

The  development  of  aleurone  grains  may  be  best  studied  in  the 
ripening  seeds  of  the  peony. 

76. — As  with  the  grains  of  aleurone,  the  nature  of  crystal- 
loids is  not  fully  understood.  They  are  quite  certai  nly  modifi- 
cations of  protoplasm,  and  not  true  crystals,  although  they 
are  bounded  by  plane  surfaces,  have  sharp  edges  and  angles, 
and  when  viewed  by  polarized  light  bear  a  resemblance 
to  crystals.  Their  deportment  with  reagents,  however, 
is  similar  to  that  of  protoplasm  ;  thus,  under  treatment 
with  iodine,  or  nitric  acid  and  potash,  and  in  their  coagula- 
bility, they  show  a  protoplasmic  nature.  They  possess  the 
power  of  imbibing  water,  but  are  not  dissolved  in  it,  and  in 
a  dilute  solution  of  potash  they  swell  greatly,  at  the  same 
time  altering  their  angles.  They  are  insoluble  in  alcohol. 
In  dilute  acids  or  glycerine  one  portion  of  their  substance  is 
removed,  leaving  a  skeleton. 

77. — In  form  they  are  cubical,  tetrahedral,  octahedral, 
rhombohedral,  and  of  other  shapes,  and  there  is  generally 
such  irregularity  in  their  forms  that  it  is  difficult  to  deter- 
mine to  which  crystal  system  they  belong.  In  most  cases 
they  are  colorless,  but  in  some  plants  they  contain  a  coloring- 
matter  which  may  be  removed  by  alcohol  and  acids. 

(a)  Common  examples  for  study  may  be  obtained  from  the  parenchy- 
ma-cells beneath  the  skin  of  the  potato  tuber,  in  which  they  are  cubi- 
cal or  tetrahedral,  and  imbedded  in  the  protoplasm. 

They  may  be  obtained  from  the  Brazil-nut  (Bertholletia  excclsa)  by 
placing  portions  of  the  crushed  seed  in  a  test-tube  and  agitating  it  with 
ether  ;  the  crystalloids,  which  settle  to  the  bottom,  are  tabular. 


CRYSTALS.  59 

Thin  sections  of  the  seeds  of  the  Castor  Bean  (Ricinus  communvi), 
after  the  removal  of  other  substances  by  soaking  in  water  for  some 
time,  show  tetrahedral  or  octohedral  crystalloids. 

(6)  Alenrone  and  the  crystalloids  furnish  the  greater  part  of  the  al- 
buminoid portions  of  edible  grains.  The  amount  of  albuminoids  is 
presumably  an  indication  of  the  amount  of  aleurone  and  crystalloids. 
The  percentage  of  albuminoids  in  some  air-dry  grains  and  seeds  is  given 
below:* 

Rice 7.5 

Barley 9.5 

Indian  Corn 10. 

Oats 12. 

Wheat 13. 

Pea 22.4 

Bean 25.5 

Vetch 27.5 

Lupine 34.5 

Aleurone  and  the  crystalloids  appear  to  be  resting  states  of  proto- 
plasm analogous  to  the  resting  states  (sclerotia)  of  the  plasmodia  of 
Myxomycetes. 

§  IV.   CRYSTALS. 

78. — In  many  plants  crystals  of  various  forms  occur  either 
in  the  cavities  of  cells,  or  in  the  substance  of  the  cell-walls, 
or  even  in  intercellular  spaces.  They  are,  in  the  greater 
number  of  cases,  composed  of  calcium  oxalate,  and  are  widely 
distributed  throughout  the  vegetable  kingdom,  but  appear 
to  be  most  numerous  in  the  higher  groups,  and  least  so  in 
Bryophytes  and  Pteridophytes. 

79. — It  is  common  to  distinguish  the  acicular  (needle- 
shaped)  crystals  from  the  other  forms  under  the  name  of 
Raphides ;  these  have  but  two  equivalents  of  water  of  crys- 
tallization in  their  composition  ([Ca  0],  C4  0B+  2  H,  6). 
They  are  found  in  the  cavities  of  parenchyma-cells,  and  lie 
parallel  together  in  bundles  of  ten  to  fifty  or  more.  Upon 
slight  pressure  the  crystals  separate  and  escape  (Fig.  46). 

The  other  crystals  of  calcium  oxalate  assume  various 
forms,  such  as  prisms,  octahedra,  etc.  They  have  six  equiv- 

*  These  percentages  are  from  Wolff  and  Knop's  tables,  an  given  by 
Professor  S.  W.  Johnson  in  his  valuable  "  How  Crops  Grow." 


60 


BOTANY. 


alents  of  water  of  crystallization  ([Ca  0],  C4  O.-f  6  H,0). 

They  may  be  simple  (Fig.  47)  or  combined  into  compound 
crystals  (Fig.  46)  ;  many  of 
the  former  are  sometimes 
found  imbedded  in  the  sub- 
stance of  the  cell-wall  of  the 
fibre-cells  of  certain  Gymno- 
sperins  (Fig. 
47).  Simple 
crystals  oc-, 
cur  also  with- 1 
in  the  cell- 
rig.  46. -Crystals  of  calcium  oxalate.  Cavities  of 

The  right-hand  portion  of   the   figure    rr,01T,T-,-,lQrifo 

shows  two  raphia-cell*  of  the  Khubarb,     many  plants. 

with  their  contained  raphides,  and  one    rPl1p       P  n  rn 

crystal  enlarged.    On  the  left  is  a  crys-     J 

tal  from  the  beet.    Much  magnified.  pound  f  Orm.8 

are  very  various ;  they  almost  always 
occur  in  cell-cavities,  as  in  the  beet  (Fig. 
46)  ;  and  it  not  infrequently  happens  that 
both  simple  and  compound  crystals  are 
found  in  the  same  plant,  even  in  contigu- 
ous cells,  as  is  the  case  in  the  onion  bulb. 

80.  —  Crystals  of  calcium  carbonate 
(Ca  C03)  occur  less  frequently  than  those 
just  described.  Their  most  striking  form 
is  that  seen  in  the  structures  named  cys- 
toliths  (Fig.  48).  These  possess  a  curious 
structure  ;  a  club-shaped  or  stalked  out- 
growth of  cellulose  projects  into  the  in- 
terior of  a  cell,  and  upon  and  in  this  mul- 
titudes of  small  crystals  are  grouped. 
Other  forms  of  calcium  carbonate  crys- 
tals are  to  be  found  in  plants — e.g.,  in  the 
Myxomycetes.  Fig  47._Crystais  of 

According  to  some  observers,  crystals  £SSSi  2?"  rJ&»SJSa 
of  calcium  phosphate,  calcium  sulphate,  miraHUf. -\ttar  Sachs. 
and  silica  are  occasionally  to  be  met  with  in  plants.* 

*  See  an  article  on  plant-crystals  by  Dr.  Lancaster  in  the  Qr.  Jr.  of 
Mic.  Science,  1863,  p.  243  ;  also  articles  by  Professor  Gulliver  in  the 
game  journal  for  18^4,  18flft  and  18^9. 


CRYSTALS. 


(51 


(a)  In  studying  plant-crystals  it  is  only  necessary  in  tuost  cases 
to  make  thin  longitudinal  sections,  and  to  mount  in  the  usual  way 
in  water. 

(6)  The  calcium  carbonate  crystals  may  be  distinguished  from  those 
of  calcium  oxalate  by  treatment  with  hydrochloric  acid,  which  dissolves 
both,  the  former  with  effervescence,  the  latter  with  none.  Under 
treatment  with  acetic  acid  the  calcium  carbonate  crystals  dissolve  (with 
effervescence,  of  course),  while  those  of  calcium  oxalate  do  not  dissolve. 

(c)  Acicular  crystals,  or  raphides,  may  be  best  obtained   from  the 
Evening  Primrose,  Epilobium,  Fuchsia,  and  other  Onajrraceae,  also  from 
the  Balsam  (Impatiens    BalKt,mi><a),  Garden  Rhubarb,  and   the  new 
growths  of  the  Virginia  Creeper,  and  the  grape-vine. 

Raphides  may  also  be  obtained  from  some  of  the  Monocotyledons 
with  equal  ease,  e.g.,  Tradescantia,  Indian  turnip  (Aristema),  Catta, 
Narcissus,  Lily-of-the-Valley,  etc. 

(d)  The  other  crystal  forms  are  obtainable  from  the  bark  of  the  lo- 
cust (Eobinin),  elm,  Iloya,  leaves  of  Begonia,  bulb-scales  of  onion, 
garlic,  and  leek,  the  root-stock  of  Iris,  etc. 

(e)  Cystoliths  may  be  readily  studied  by  making  cross- sections  of 
the  leaves  of  Urticfi,  mulberry,  hop,  hemp,  fijr,  Celtis,  and  other  Urti- 
cnceoi.    They  are  said  by  Sachs  to  occur  only  iu  this  order  and  the 
AcanthacecB.* 


Fipr.  48.— Cystolith  from  the  epidermis  of  the  upper  surface  of  the  'eaf  of  Urtica 
rnucivp/tylla,  from  a  cross  section  of  the  leaf.  X  225.— After  Ue  Bury. 

(/)  Plant-crystals  appear  to  be  surrounded  by  a  thin  layer  of  proto- 
plasm ;  probably  they  are  separated  out  from  the  cell  sap  only  through 
the  influence  of  protoplasm.  It  is  further  probable  that  they  are  resid- 
ual products  of  chemical  actions  in  the  plant,  and,  as  they  appear  never 
to  be  made  use  of  by  the  plant,  we  must  regard  them  aa  to  a  certain 
extent  of  the  nature  of  excretions. 


*"Lehrbuch,"  4te  auf.,  p.  69.  However,  cystoliths,  or  structures 
very  much  like  them,  may  be  found  in  the  leaves  of  Ceanothus  prostra- 
t its  of  Nevada  and  California.  The  student  is  referred  to  De  Bary's 
"  Vergleichende  Anatomic  der  Vcgetationsorpjane  der  Phanemgarnen 
und  Fame,"  Chapters  I.  and  III.,  for  a  full  discussion  of  the  subject  of 
plant  crystals,  and  for  a  lisi  of  plants  containing  them.  The  articles 
referred  to  in  Qr.  Jour.  Mic.  Science  will  also  prove  helpful. 


62  BOTANY. 

§  V.   THE  CELL  SAP. 

81. — All  parts  of  a  living  cell  are  saturated  with  water.  It 
enters  into  the  structure  of  the  cell-wall ;  it  makes  up  the 
greater  part  of  the  bulk  of  the  protoplasm,  and  it  fills  the 
vacuoles.  It  holds  in  solution  (not  necessarily,  however,  in 
equal  proportions  in  all  its  parts)  the  food-materials  absorbed 
by  the  plant,  and  the  surplus  soluble  products  of  assimila- 
tion and  metastasis. 

82. — Among  the  more  important  substances  dissolved  in 
the  cell  sap  are  Sugar  and  Inuline.  Of  the  former  there 
are  two  varieties,  viz.,  sucrose,  or  cane  sugar  (C12  Ha2  On), 
and  glucose  (or  laevulose),  or  fruit  sugar  (Cia  II24  Oia),  which 
differ  in  their  sweetness,  as  well  as  in  other  properties. 

83. — Cane  sugar  exists  in  great  abundance  in  the  cell  sap 
of  sugar  cane,  sugar  maple,  sugar  beet,  Indian  com,  and  in 
greater  or  less  quantity  in  nearly  all  higher  plants.  Fruit 
sugar,  as  its  name  indicates,  is  found  in  many  fruits,  some- 
times mixed  with  cane  sugar  ;  thus  in  grapes,  cherries, 
gooseberries,  and  figs  it  is  the  only  sugar  present,  while  in 
apricots,  peaches,  pine-apples,  plums,  and  strawberries  it  is 
mixed  with  cane  sugar. 

84.  —Inuline  (Cia  H20  010)  is  a  substance  related  to  starch 
and  sugar,  and  found  mainly  in  certain  Composite,  e.g., 
Dahlia,  Helianthus,  Inula,  Taraxacum,  etc.  It  may  be 
separated  from  the  cell  sap  by  alcohol,  glycerine,  and  other 
agents,  and  it  then  assumes  the  form  of  sphere-crystals.  By 
boiling  in  dilute  hydrochloric  or  sulphuric  acid  inuline  is 
transformed  into  glucose. 

§  VI.    OILS,  KESINS,  GUMS,  ACIDS,  AXD  ALKALOIDS. 

85. — The  fixed  oils,  as  olive,  castor,  linseed,  and  palm  oil, 
are  secreted  in  many  plant-cells,  particularly  in  the  seeds. 
They  occur  as  separated  drops  among  the  other  contents  of 
the  cells.  In  some  instances  the  tissues  contain  from  thirty- 
five  to  forty  per  cent  of  oil. 

86. — The  essential  oils,  the  resins,  and  gums  are  mainly 
the  products  of  special  cells  in  the  plant,  These  secreting  cells 


OILS,  RESINS,   ETC.  63 

are  usually  thin- walled  and  filled  with  granular  protoplasm. 
The  secretions  are  in  some  cases  collected  in  drops  in  the 
cell-cavity,  in  others  they  are  caused  to  pass  through  the 
cell-wall,  while  in  still  other  instances  the  cell- wall  ruptures, 
and  permits  the  escape  of  the  secreted  matter. 

87. — There  are  three  classes  of  essential  oils,  distinguished 
by  their  chemical  composition,  as  follows  : 

(a)  The  pure  hydrocarbons ;  these  are  represented  by  the 
formula  CJO  Hlg.    Oil  of  turpentine,  obtained  from  the  crude 
turpentine  of  various  Conifers,  is  the  type.     Oil  of  lemons, 
oil  of  caraway,  and  oil  of  thyme  are  also  of  this  class. 

(b)  The  oxidized  essences,  in  addition  to  carbon  and  hy- 
drogen, have  oxygen  in  their  composition.     Of  this  nature 
are  camphor  (CIO  H16  0),  essence  of   cinnamon,  essence  of 
wintergreen,  etc. 

(c)  The  sulphuretted  essences  contain  sulphur.     To  this 
class  belong  the  essential  oils  in  mustard,  horseradish,  and 
other  Cruciferae,  in  onions,  garlic,  asafoetida,  etc.     That  in 
garlic,  which   may  be   taken  as  the  type,   is  a  sulphide, 
([C3HJ2,  S),  while  that  of  the  mustard  is  a  sulpho-cyanide 
(CSHB,  CNS). 

88. — Resins  are  much  like  the  essential  oils  in  composition, 
and  are  generally  associated  with  and  dissolved  in  them. 
When  separated  from  the  essential  oils  by  heat,  the  resins  are 
transparent  or  translucent  brittle  solids,  insoluble  in  water, 
but  soluble  in  alcohol.  Common  rosin,  which  is  the  resi- 
due left  when  the  crude  turpentine  derived  from  several  spe- 
cies of  pines  is  distilled  with  water,  maybe  taken  as  the  type. 
It  is  an  oxidized  hydro-carbon,  i.e.,  it  contains  carbon,  hy- 
drogen, and  oxygen. 

89. — Gums.  Under  this  name  many  different  kinds  of 
products  are  commonly  included.  Some  of  them  are  with- 
out doubt  related  to  the  resins,  while  others  are  allied  to 
starch  and  sugar.  Of  the  latter  kind  gum-arabic  (Clt  HM  On) 
is  the  type,  and  allied  to  it  are  cerasin  (from  the  cherry), 
bassorin  (gum  tragacanth),  and  vegetable  mucilage,  which 
is  abundant  in  mallow  roots. 

90.— Pectin,  or  vegetable  jelly  (C3a  H48  OJ,  is  related  to 
the  foregoing  ;  it  forms,  when  moist,  a  transparent  jelly,  and 


64  BOTANY. 

dries  into  a  translucent  mass.  It  gives  the  firmness  and  con- 
sistence to  apple,  currant,  and  other  fruit  jellies.  Unripe 
fruits  contain  a  substance  insoluble  in  water,  alcohol,  and 
ether,  which,  during  the  process  of  ripening,  or  under  the 
action  of  heat,  acids,  and  ferments,  is  converted  into  pectin. 
91. — In  addition  to  oxalic  acid  (Ca  H2  04),  which  is  found 
generally  combined  with  calcium,  there  are  other  vegetable 
acids,  some  of  which  are  even  more  common ;  they  occur 
either  free,  or  united  with  organic  or  inorganic  bases. 

(a)  Malic  Acid  (C4  H8  06)  is  abundant  in  many  sour  fruits 
— e.g.,   apples,    cherries,    strawberries,  currants,  etc.;  it  is 
likewise  abundant  in  rhubarb,  where  it  accompanies  oxalic 
and  phosphoric  acids. 

(b)  Tartar ic  Acid  (C4  HB  08)  occurs  in  the  grape,  tama- 
rind, berries  of  the  mountain  ash  (unripe),  and  other  plants. 

(c)  Citric  Acid  (C,  HB  07)  is  found  in  abundance  in  the 
lime,  lemon,  and  other  fruits  of  the  Aurantiacese.     It  also 
occurs  in  other  sour  fruits  associated  with  malic  acid,  as  in 
gooseberries,  raspberries,  strawberries,  cherries,  etc. 

(d)  Tannic  Acid  (CS7  Ha!I  017)  occurs  in  the  bark  and 
leaves  of   oak,  elm,   willow,  and  many  other  trees,  in  the 
wood  and  bark  of  sumach  and  whortleberry,  and  the  roots  of 
some  Rosaceae  and  Polygonacea?,  and  gives  to  them  their  as- 
tringency. 

Nearly  related  to  tannic  acid  is  quinic  acid,  which  occurs 
in  the  bark  of  Cinchona  (Peruvian  Bark)  in  combination 
with  organic  bases,  of  which  quinia  is  the  most  important. 

There  are  many  other  substances  which  occur  in  plants  as 
the  products  of  cells — e.g.,  the  vegetable  alkaloids,  many 
coloring-matters,  etc.  As,  however,  this  whole  matter  be- 
longs rather  to  Organic  Chemistry,  it  will  not  be  carried 
further  in  this  place. 


CHAPTER  VI. 

TISSUES. 
§  I.   THE  VARIOUS  AGGREGATIONS  OP  CELLS. 

In  the  organisms  which  compose  the  vegetable  kingdom 
cells  are  found  principally  under  the  following  conditions  of 
aggregation : 

92. — (1.)  Single  Cells.  A  large  number  of  the  lower 
plants,  during  all  or  a  considerable  part  of  their  existence, 
are  composed  of  single  cells  They  may  be  round,  as  in 
Saceharwnyces  and  Protococcus,  or  elongated  or  even  filiform, 
as  in  certain  Bacteria.  It  is  only  in  the  lowest  groups  that 


f*-— JVJiMgriMi  grfm*lat>a».  A.  the  youw-  cells  ?n  their  motile  rtatp  en- 
««*a  in  the  membrane  of  the  mother-cell  B,  the  young  cells  beginning  to  •mn»c 
themselves  in  a  cell-family.  C.  the  cell-family  fully  developed.- After  Braun. 

adult  plants  are  composed   of  single  cells,   but  it  is  an 
embryonic  condition  of  all  others. 

93.— (2.)  Families,  or  Spurious  Tissues.  There  are 
some  oases  in  which  cells  which  are  at  first  distinct  after- 
wards become  united  more  or  less  closely  into  a  common 
mass,  vhich  may  be  denominated  a  Cell-Family,  or  Spurious 
Tissue. 

(a)  Pediaitrum  and  Hydrodietyon  furnish  the  best  examples  of  true 


66  BOTANY. 

cell-families  ;  in  both  cases  separate  motile  cells  (zoospores)  in  a  mother- 
cell  arrange  themselves  in  a  definite  manner,  and  gradually  unite  into 
a  family  resembling  the  parent  plant  (Fig.  49).  By  the  breaking  up  of 
the  wall  of  the  mother-cell  the  new  family  is  set  free. 

(6)  In  some  fungi  the  cells  composing  the  vegetative  threads  (hy- 
phae)  unite  loosely  with  one  another  into  a  mass.  In  some  cases  the 
union  is  so  slight  that  the  hyphae  may  be  separated  with  the  greatest 
ease,  while  in  others  it  approaches'  the  density  and  firmness  of  true 
tissues  (Fig.  50).  While  the  term  Cell-Family  may  be  applied  to  such 
aggregations  of  cells,  the  common  one  of  Spurious  Tissue  is  to  be  pre- 
ferred * 

(c)  In  the  embryo  sac  of  Phanerogams  the  cells  are  at  first  separate ; 


Fig.  60.  —  Rhlzomorpha  subcorticalte  (the  compact  mycelium  of  a  fungus).  The 
left  hand  flaure  shows  a  longitudinal  section  of  the  growing  end  of  a  young  shoot. 
The  right  hand  figure  shows  a  cross-section  of  the  same  ;  a,  the  central  pith-like  por- 
tion ;  o,  the  cortical  portion  of  smaller  cells  ;  A,  the  hairy  coat,  which  is  often 
wanting.  X  100.— After  De  Bary. 

these  afterward  unite  into  a  mass  which  cannot  be  distinguished  by 
any  structural  character  from  a  true  tissue.  (See  Fig.  33,  p.  43.)  As, 
however,  the  component  cells  were  originally  separate,  the  resulting 
mass  must  be  classed  with  the  spurious  tissues. 

94 — (3.)  Fusions.  It  frequently  happens  that  the  separat- 
ing walls  of  contiguous  cells  are  absorbed  and  their  cell- 
cavities  merged  into  one.  In  this  way  long  tubes  (vessels) 


This  i.-s  the  "  Tela  coutexta''  of  some  authors. 


THE  AGGREGATIONS  OF  CELLS.  6? 

are  formed.  These  may  extend  in  any  direction,  but  they 
generally  run  parallel  to  the  axis  of  that  part  of  the  plant  in 
which  they  are  found.  Other  cell-fusions  give  rise  to  irreg- 
ular branching  tubes,  or  they  may  even  form  an  extended 
network  (e.g. ,  in  the  laticif erous  tissue  of  Cichoriaceae,  Fig. 
65,  p.  75). 

95. — (4.)  Tissues.  A  tissue  may  be  defined  as  an  aggre- 
gation of  similar  cells  (or  cell-derivatives)  connately  united. 
There  are  three  conditions  of  aggregation  : 

(a)  Cell-rows.  In  these  the  cells  are  united  by  their  ends 
into  a  row  or  filament.  Such  simple  tissues  result  from  cell- 
fission  in  one  direction  only.  In  some  cases,  as  in  Oscilla- 


Fig.  51. — Succulent  parenchyma  from  the  stem  of  Indian  corn  ;  transverse  flection. 
yw,  simple  p)ate  of  cellulose,  forming  the  partition-wall  between  two  cells;  2,2, 
intercellular  spaces  caused  by  splitting  of  the  walls  during  rapid  growth.  X  550. 
—After  Sachs. 

toria,  the  cells  are  short  and  broad,  while  in  others — e.g., 
Spiroyyra,  Zygnema,  and  the  hyphae  of  many  fungi — they 
are  cylindrical  or  greatly  elongated.  Numerous  cases  occur 
in  the  higher  plants,  the  most  familiar  being  jointed  hairs. 

(b)  Cell-surfaces  are  composed  of  a  single  layer  of  cells. 
They  result  from  cell-fission  in  two  directions.     Examples 
may  be  found  in  many  Ulvaceae,  and  in  the  leaves  of  somo 
Bryophytes. 

(c)  Masses.     Where  the  cell-fission  has  been  in  three  di- 
rections the  result  is  a  mass  of  greater  or  less  solidity.     Fre- 
quently, through  cell-fusions,  the  elements  which  compose 
such  masses  are  cell-derivatives,  instead  of  cells  ;  these  may 
be  regarded  as  tissues  of  a  higher  order. 


68  BOTANY 

96. — The  Cell-wall  in  Tissues.  In  tic  sues  the  walls  which 
separate  contiguous  cells  are  at  first  simple  and  homogeneous. 
The  plate  of  cellulose  which  first  forms  between  two  sister 
masses  of  protoplasm  in  cell-fission  is  a  single  one,  the  com- 
mon property,  as  it  is  the  common  secretion,  of  the  proto- 
plasm masses.  As  the  wall  becomes  older  and  thicker,  and 
stratification  takes  place,  it  shows  a  line  of  separation  into 
two  halves  ;  this  may  become  so  well  marked  as  actually  to 
result  in  the  splitting  of  the  wall,  as  is  the  case  in  succulent 
tissues  when,  on  account  of  a  particular  kind  of  tension, 
intercellular  spaces  are  formed  in  the  angles  between  the 
cells  (Fig.  51). 

97. — By  a  still  further  differentia- 
tion, after  a  considerable  thickness  of 
the  wall  has  been  attained,  there 
may  arise  a  common  middle  lamella, 
which  appears  at  first  sight  to  lie 
between  the  original  cell-walls  (Fig. 
52).  This  middle  lamella,  which  is 
simply  the  result  of  a  particular 
stratification,  was  long  mistaken  for 
an  intercellular  substance,  and  two 
pangof  thf  yOTDgth8teriS0S  theories  were  held  as  to  its  nature.  On 
Bece,io8nUTcS  ofcTf™  the  one  hand,  it  was  supposed  to  be 
pJrUonsTf6'^!*'  'x^soo-  an  original  common  matrix,  in  which 
After  Sachs.  t]ie  C(,\\s  themselves  were  imbedded  ; 

and  on  the  other,  it  was  held  to  be  of  the  nature  of  an  ex- 
cretion from  the  surrounding  cells  into  the  intercellular 
spaces.  The  first  of  these  theories  was  possible  only  so  long 
as  the  knowledge  of  the  origin  and  development  of  cells  was 
exceedingly  defective.  The  second  theory  is  rendered  ex- 
tremely improbable  by  our  present  knowledge  of  the  mode 
of  growth  of  the  cell-wall  by  intussusception. 

Until  recently  another  view  has  been  largely  held,  name- 
ly, that  the  middle  lamella  was  to  be  regarded  as  the  original 
common  wall  of  the  cells,  and  that  the  remaining  portions 
were  after-deposits  upon  it.  This  view  gave  rise  to  the  terms 
Primary  Cell-Avail  and  Secondary  Cell-wall,  which  are  still 
used  to  some  extent.  As  this  explanation  of  the  structure 
rests  upon  the  all-but-abandoned  theory  of  the  thickening 


THE  PRINCIPAL   TISSUES. 


of  the  cell-wall  by  the  addition  of  successive  internal  layers, 
and  is  directly  contradicted  by  the  well-established  doctrine 
of  growth  by  intussusception,  it  must  be  regarded  as  erroneous. 
In  some  cases,  as  in  the  wood  of  Pinus  sylvestris,  the  dif- 
ferentiation is  so  great  that  three  lamellae  are  formed  :  (1) 
the  common  middle  one,  (2)  an  inner,  and  (3)  an  inter- 
mediate one.  (Fig.  16,  p.  26.) 

§  II.    THE  PRINCIPAL  TISSUES. 

98. — There  are  very  many  kinds  of  tissues,  distinguished 
from  each  other  by  characters  of 
greater  or  less  importance. 
They  all,  however,  pass  into 
one  another  by  almost  insensi- 
ble gradations  ;  hence  by  not- 
ing all  the  slight  differences  we 
may  make  a  long  list  of  tis- 
sues ;  while  by  noting  the  simi- 
larities and  gradations,  all,  or 
nearly  all,  the  forms  may  be  re- 
duced to  one.  The  principal 
varieties  only  will  be  noticed  in 
this  place;  each  one,  as  here 
described,  includes  many  varie- 
ties. 

99. — Parenchyma.  This  is 
the  most  abundant  tissue  in  the 
vegetable  kingdom  ;  it  is  at  once 
the  most  important  and  the 


Fi?.  53— Meristem-cells  of  stem  of 
faba  in  process  of  division.    X 


most  variable.  As  here  restrict-  »»— After  Pranti. 
ed  it  is  composed  of  cells  whose  Avails  are  thin,  colorless,  or 
nearly  so,  and  transparent ;  in  outline  they  may  be  rounded, 
cubical,  polyhedral,  prismatic,  cylindrical,  tabular,  stellate, 
and  of  many  other  forms.*  When  the  cells  are  bounded  by 
plane  surfaces,  generally,  but  not  always,  the  end  planes  lie 
at  right  angles  to  the  longer  axis  of  the  cells. 

*  Unfortunately,  the  terms  parenchyma  and  parenchymatous  have 
often  heen  restricted  in  meaning  to  tissues  composed  of  cells  whose 
three  dimensions  are  equal. 


70 


BOTA  A  r. 


This  tissue  makes  up  the  whole  of  the  substance  of  many 
of  the  lower  plants.  In  the  higher  plants  the  essential  por- 
tions of  the  assimilative  (green),  vegetative  (growing),  and 
reproductive  parts  are  composed  of  parenchyma. 

Instructive  examples  of  parenchyma  may  be  obtained  in  the  growing 
ends  of  shoots  (Fig.  53)  and  in  the  pith  of  Dicotyledons,  in  the  ends  of 
young  roots — t.  g.,  of  Indian  corn— in  the  green  pulp  of  leaves,  iu  the 
pulp  of  fleshy  fruits,  and  in  the  substance  of  young  embryos. 

10O.— Collenchyma.  The 
cells  of  this  tissue  are  elon- 
gated, usually  prismatic,  and 
their  transverse  walls  are  most 
frequently  horizontal,  rarely 
inclined.  With  few  excep- 
tions* there  are  no  intercellu- 
lar spaces.  The  walls  are 
greatly  thickened  along  their 
longitudinal  angles,  while  the 
remaining  pans  are  thin  (Fig. 
21.  p.  30).  The  cells  con- 
tain chlorophyll,  and  retain 
the  power  of  fission,  f  Wet 
specimens  show  by  transmit- 
ted light  a  characteristic  blu- 
ish white  lustre  (Figs.  54  and 
55). 

Colleuchyina  is  found  be- 
neath the  epidermis  of  Dico- 
tyledons (and  some  ferns). 
usually  as  a  mass  of  conside- 
rable thickness,  and  is  doubtless  developed  from  parenchyma 
for  the  purpose  of  giving  support  and  strength  to  the  epi- 
dermis. 


F5g.  54. — Trans yerse  section  of  collen- 
chj-ma  (00)  of  the  stem  of  R'hinocyttu 
lobata.  wet  with  water,  and  the  arigks 
jrrcatly  swollen.  ei>.  epidermis,  with 
thickened  outer  wall  x  TOO.  " 
drawing  by  J.  C.  Arthur. 


From  a 


*  In  the  eollenrliyma  of  SilpMum  pfrfoliatum  there  are  many  lon- 
gitudinal intercellular  spaces  of  various  sizes  ;  in  fptnmrn  purptirea 
there  are  minnte  ones. 

f  De  Bary  states  that  collenchyma-oells  are  capable  of  fission. 
' •  Verjjleichende  Anatomit-  dr r  VegetatiousorgaDe  der  Phauerogam.  n 
und  Faroe,"  p.  126. 


TIIE  PRINCIPAL    TIMUE8.  71 

(a)  Collenchyma  may  be  studied  in  the  stems,  petioles,  and  leaf-ribs 
of  herbaceous  Dicotyledons — e.g.,  in  species  of  fyttpfdum,  Rheum, 
Rums.x,  Chenopodium — in  many  Labiate,  txdanacece,  Begoniaceoe,  Gu. 
curbitacece,  and  many  others;  also  in  the  petioles  of  the  water-lilr 
and  young  stems  of  the  elder. 

(6)  Upon  soaking  in  water,  or  upon  treatment  with  nitric  or  sulphu- 
ric acid,  the  thickened  angles  become  greatly  swollen. 


Fie.  55.— Longitudinal  radial  section  of  stem  of  EcJiittocystit  tobala.  ep,  epidermic ; 
oo,  collenchvma  ;  pa,  parenchyma :  /,  a  single  wood  fibre,  marked  with  "  crossed " 
(i.e.,  twisted)  piu> ;  tji,  intercellular  spaces,  x  500.  Prom  a  drawing  by  J.  C.  Arthur. 

(e)  Upon  treatment  with  Schultz's  Solution  the  thickened  angles  are 
colored  light  blue. 

(d)  Upon  slight  warming  in  a  solution  of  ix>tash,  and  then  treaties 
with  a  solution  of  iodine  in  potassium  iodide,  the  thickened  angles  be- 
come colored  dark  blue. 

1O1.— Sclerenchyma.  In  many  plants  the  hard  parts  are 
composed  of  cells  whose  walls  are  thickened,  often  to  a  very 


72  BOTANY. 

considerable  extent.  The  cells  are  usually  short,  but  in  some 
cases  they  are  greatly  elongated  ;  they  are  sometimes  regular 
in  outline,  but  more  frequently  they  are  extremely  irregular. 
They  do  not  contain  chlorophyll,  but  in  some  cases  at  least 
(e.g.,  in  the  scleienchyma-cells  in  the  pith  of  apple-twigs) 
they  contain  starch. 

Sclerenchyma  occurs  in  Bryophytes,  Pteridophytes,  and 
Phanerogams. 

(a)  Good  specimens  of  sclerenchyma  may  be  obtained  for  study  by 
making  longitudinal  sections  of  the  rhizome   of  Pteris  aquilina,    in 


Fio.  565. 


FIG.  56^4. 


Fio.  57. 


Fig.  56. — Two eclerenchyma-cells  from  the  hypoderma  of  the  rhizome  of  Pteris 
aquilina,  isolated  by  Sclmtze's  maceration.  A,  a  very  thick-walled  cell,  with  branch- 
ing pits;  B,  a  cell  with  walls  less  thickened— the  wall  of  the  opposite  side  of  the 
cell  is  seen  to  be  filled  with  numerous  pits.  X  500. — After  Sachs. 

Fig.  57. — Margin  of  leaf  of  PinusjAnaster,  transverse  section,  c,  cuticularized  layer 
of  outer  wall  of  epidermis  ;  i,  inner  non-cuticularized  layer ;  c',  thickened  outer 
wall  of  margin  il  cell ;  g,  i',  hypoderma  of  elongated  s  lerenchyma  ;  j>,  chlorophyll- 
bearing  parenchyma  ;  pr,  contracted  protoplasmic  contents,  x  800.— After  Sachs. 

which  it  occurs  as  a  thick  hypodermal  mass  ;  by  boiling  in  potassium 
chlorate  and  nitric  acid  (Scliulze's  maceration)  the  cells  may  be  com- 
pletely isolated  (Fig.  56,  A  and  B). 

(b)  The  cells  of    the  medullary  rays  of  woody  Dicotyledons— e.g., 
Acer,  Pirus,   Ostrya,   Liriodendron,  etc. — are  generally  thick-walled 
when  old.  and  in  this  state  must  be  classed  as  sclerenchyma. 

(c)  The  hypoderma  of  the  leaves  of  pines  consists  of  elongated  scle- 
nmchyma-cells,  which  at  first  sight  might  easily  be  mistaken  for  bnst 
fibres  (Fig.  57,  rj,  £).     The  hypoderma  of  many  other  plants  appears  to 
be  of  a  similar  nature. 


THE  PRINCIPAL   TISSUES.  73 

(d)  The  bard  tissues  of  nuts  and  of  stone  fruits  furnish  excellent  ex- 
amples of  short  and  very  thick- walled  sclerenchy  ma-cells.  In  the 
hickory  nut  (Carya  alba)  the  cells  (Figs.  58  and  59)  are  not  more  than 


Fig.  58.  —  Sclerenchyma-cells  of  the  shell  (endocarp)  of  the  hickory-nut  (Carya 
alba),  taken  parallel  to  the  surface  of  the  nut.  X  400. 

Fig.  59.— Sclerenchyma-cells  of  the  shell  (endocarp)  of  the  hickory-nut  (Carya 
alba),  taken  at  right-angles  to  the  surface  of  the  nut.  X  400. 

two  or  three  times  as  long  as  broad,  and  the  thickening  is  so  great  as 
almost  entirely  to  obliterate  their  cavities;  the  thickened  walls  are 


fee. 


Fro.  61. 


Fig.  60.  —  Sclerenchyma  cells  of  thv  seed-coat  of  Echinocystis  lobata,  from  a  section 
at  right  angles'to  the  surface  of  the  seed  ;  a,  a  cell  cut  directly  through  its  centre. 
showing  the  whole  of  the  cavity—  the  three  dark  spots  are  probably  oil  ;  b,  a  cell 
cut  through  at  one  side  of  the  middle  ;  c,  a  cell  whose  cavity  was  not  cut  into  in 
making  the  section.  X  250.  From  a  drawing  by  J.  C.  Arthur. 

Fig.  61.—  Sclerenchyma-cells  of  the  seed-coat  of  BdHnocygfts  lobala,  from  a  section 
parallel  to  the  surface  of  the  seed,  x  250.  From  a  drawing  by  J.  C.  Arthur. 


pierced  by  many  deep  pits.  The  cells  are  arranged  with  their  longer 
axes  perpendicular  to  the  surface  of  the  nut,  and  are  very  closely 
packed  together. 


74 


BOTANY. 


(e)  The  seed-coat  of  Echinocystu  lobata  is  composed  almost  entirely 
of  sclerenchyma  (Fig.  60).  The  cell-walls  are  greatly  thickened,  and 
the  cells  are  very  closely  packed  together,  so  much  so  that  all  are 
sharply  prismatic  (Fig.  61). 

102.— Fibrous  Tissue.  This  is  composed  of  elongated, 
thick-walled,  and  generally  fusiform  elements,  the  fibres 
(Figs.  62  and  63),  whose  walls  are  usually  marked  with 
simple  or  sometimes  bordered  pits.  These  elements  in  cross- 
section  are  rarely  square  or  round,  but  most  generally  three 
to  many-sided.  They  are  found  in,  or  in  connection  with. 
the  fibro-vascular  bundles  of  Pteridophytes  and  Phanero- 
gams,and  give  strength  and  hardness  to  their  stems  and  leaves. 


PIG.  62.  Fio.  63. 

Fip.  82.— Wood  fibres  of  Acer  dcuycarpum.  isolated  by  Schulze's  maceration,  a, 
four  fibres,  x  95 ;  b,  a  portion  of  a  fibre,  x  230,  showing  the  diagonally  placed  elon- 
gated pita  ;  c,  the  ends  of  eleven  united  fibres.  X  95. 

Fig.  63.— Bast  fibres  of  Acer  dasycai~pym,  isolated  by  Schulze's  maceration,  a,  a 
fibre,  x  96  ;  6,  a  portion  of  a  fibre,  X  230,  showing  the  much-thickened  wall. 

Two  varieties  of  fibrous  tissue  may  be  distinguished,  viz., 
(1)  Bast  (Fig.  63),  and  (2)  Wood  (Fig.  62).  The  fibres  of 
the  former  are  usually  thicker  walled,  more  flexible,  and  of 
greater  length  than  those  of  the  latter.  In  both  forms  the 
fibres  are  sometimes  observed  to  be  partitioned.* 

*  These  partitions  liave  generally  been  considered  as  formed  subse- 
quently to  the  fibres ;  but  it  may  well  be  questioned  whether,  in  some 


THE  PRINCIPAL    TISSUES.  T5 

To  examine  fibrous  tissue  it  is  only  necessary  to  make  thin  longitudi- 
nal slices  of  the  stems  of  woody  plants — e.g.,  Acer,  Pirus,  etc. — and  to 
heat  for  a  minute  or  less  in  nitric  acid  and  potassium  chlorate.  The 


FIG.  64.  FIG.  65. 

Fig.  64.—  Laticiferous  tubes  from  Euphorbia.    A,  moderately  magnified;  B.  more 
highly  magnified,  and  showing  the  bone-shaped  or  dumb-bell-shapea  starch  grains.— 

Fig.  65. — Laticiferous  vessels  of  Scorzonera  hispanica.    A ,  a  transverse  section  of 
the  phloe'm  of  the  root ;  B,  the  same  more  highly  magnified.— After  Sachs. 

fibres  may  now  be  separated  under  a  dissecting  microscope,  or  the 
cases  at  least,  the  fibres  are  not  cell-derivatives,  and  the  partitions  the 
persistent  walls  of  the  original  component  cells. 


BOTANY. 


specimens  may  be  transferred  to  a  glass  slide  and  dissected  by  tapping 
gently  upon  the  centre  of  the  cover-glass. 

103. — Laticiferous  Tissue.  In  many  orders  of  Phanero- 
gams tissues  are  found  whose  component  elements  contain  a 
milky  or  colored  fluid — the  latex.  To  these,  although  vary- 
ing greatly  in  structure  and  position,  the  general  name  of 
Laticiferous  tissues  has  been  given.  For  the  sake  of  simpli- 
city two  general  forms  may 
be  distinguished  :  (1)  that 
composed  of  simple  or  brandl- 
ing elements  (Fig.  G4),  which 
are  scattered  through  the 
other  tissues.  As  found  in 
EupliorbiacecB,  Avhere  they  oc- 
cur in  parenchyma,  they  are 
somewhat  simply  branched, 
and  have  very  thick  walls 
(Fig.  64,  B) ;  in  other  orders 
they  are  thin  walled  and  are 
sometimes  inclined  to  anasto- 
mose. From  their  position  it 
is  quite  certain  that  the  ele- 
ments of  this  form  of  laticif- 
erous  tissue  frequently  replace 
bast  fibres.  In  such  cases 
they  are  said  to  be  metamor- 

Fig.  66— Laticiferous  cells  of  the  onion,  J  . 

from  a  longitudinal  section  of  a  scale  of  pllOSed   bast   fibres  I*  111  other 
the  bulb.    «,  epidermis  with  cuticle  c  ;  p,  ,  ., 

parenchyma ;  sg,  coagulated  contents  of  CaSCS,     however,    they    appear 
laticiferous  cells,  contracted  so  as  to  show  ,      v         r    .  i  •  -, 

the  porous  walls;  g,  g,  transverse  wall.-  not  to  be  of  this   nature,  but 

to  arise  from  the  parenchyma 
by  the  absorption  of  the  horizontal  partition- walls,  f 

*  There  is  an  objection  to  the  word  metamorphosed  in  this  connec- 
tion, as  it  does  not  exactly  express  the  relation  between  the  laticiferous 
elements  and  the  bast  fibres.  It  must  not"  be  understood  that  the 
former  are  made  by  a  transformation  of  the  formed  bast  fibres  ;  the 
relation  is  rather  that  they  develop  from  what  under  other  circum- 
stances would  have  developed  into  bast  fibres.  We  may  express  the 
relation  by  saying  that  laticiferou.3  elements  and  bast  fibres  are  closely 
related  sister  elements. 

f  "  According  to  Hanstein,  it  is  probable  that  in  some  Aroideae  vessels 


THE  PRINCIPAL   TISSUES.  77 

(2.)  The  other  form  is  that  composed  of  reticulately  anas- 
tomosing vessels.  Here  the  tissue  is  the  result  of  the  fusion 
of  great  numbers  of  short  cells.  The  walls  are  thin  and 
often  irregular  in  outline.  In  Cichoriacece  this  form  of 
laticiferous  tissue  is  very  perfectly  developed  as  a  consti- 
tuent part  of  the  phloem  portion  of  the  fibro-vascular 
bundles  (Fig.  65,  A  and  B}. 

(a)  Laticiferous  tissue  has  not  yet  been  shown  to  contain  either  pro- 
toplasm or  nucleus.*     The  latex  is  an  emulsion  of  several  substances, 
some  of  which,  as  caoutchouc  (India-rubber),  gutta-percha,  and  opium, 
are  of  great  economic  importance.    In  some  cases,  as  in  Euphorbia, 
grains  of  starch  are  contained  in  the  latex  (Fig.  64,  B). 

(b)  The  chemical  composition  of  latex  is  shown  by  the  following 
analyses,  as  given  by  De  Bary :  f 

Latex  of  Hevea  Ouianensis,  as  determined  by  Faraday  : 

Water  with  an  organic  acid 56.3  per  cent. 

Caoutchouc   31.7    " 

Albumen 1.9    " 

Bitter  nitrogenous  matter,  with  wax 7.1    " 

Residue  soluble  in  Ha  O,butinsoluble  in  alcohol.  2.9    " 


Latex  of  Galactodendron  utile,  as  determined  by  Heintz  : 

Water 57.3  per  cent. 

Albumen 0.4 

Wax  (C35  H68  O3) 5.8 

Resin  (C35  H68  Oa) 31.4 

Gum  and  sugar 4.7 

Ash 0.4 

100. 

Latex  of  Euphorbia  cyparissias,  determined  by  Weiss  and  Wiesner 

Water 72.1  per  cent. 

Resin 15.7 

Gum 36 

Sugar  and  extractive  substances 4.1 

Albumen 0.1 

Ash 0.9 

96.5 

of  the  xylem  assume  the  form  and  function  of  laticiferous  vessels.' 
Sachs'  "  Text-Book  of  Botany,"  English  edition,  p.  110. 

*  The  latex  of  some  Cichoriacese  coagulates  much  like  protoplasm , 
possibly  further  investigation  will  show  it  to  be  present. 

f  "Anatomic  der  Vegetationsorgane,"  etc.,  p.  194. 


78 


BOTANY. 


(c)  Examples  of  the  simpler  forms  of  laticiferous  tissue  may  be  ob- 
tained for  study  from  Euphorbiacece,  Urticacea,  Asclepiadacea,  Apocy- 
nacece.  Forms  less  simple  occur  in  Aracece,  and  in  the  maple  ;  in  the 
last-mentioned  they  appear  to  replace  the  sieve-vessels.  Related  to 
these  again  are  the  peculiar  milk-vessels  of  the  onion  (Fig.  66),  which 
consist  of  elongated  cells  separated  by  thin  or  perforated  septa. 


Fig.  67.  —  Longitudinal 
section  through  the  sieve 
tissue  of  Cucurbita  Pepo. 
g,  q,  section  of  transverse 
sieve  -  plates  ;  si,  lateral 
sieve-plate  ;  as,  thin  places 
in  wall  ;  /,  the  same  seen  in 
section ;  ^w,  protoplasmic 
contents  contracted  by  the 
alcohol  in  which  the  speci- 
mens were  soaked  ;  ep,  pro- 
toplasm lifted  off  from  the 
sieve-plate  by  contraction  ; 
si,  protoplasm  still  in  con- 
tact with  the  sieve-plate  ;  z, 
parenchyma  between  sieve 
tubes.  X  550.  -After 
Sachs. 


(rf)  The  more  complex  or  reticulated  forms  of  laticiferous  tissue 
occur    in    dchoriacm,   Campanulacea,  Lobdiaceoi,    Convolvulacea,  Pn- 


(e)  By  heating  thin  sections  of  any  of  the  foregoing  plants  in  a  di- 
lute solution  of  potash  the  laticiferous  tissues  may  be  readily  isolated 
for  study. 

(/)  The  walls  of  the  laticiferous  elements  are  always  rich  in  water, 
and  are  composed  of  cellulose,  as  may  be  shown  by  the  blue  coloration 
which  follows  treatment  with  Schultz's  Solution. 


TUE  PRINCIPAL    TISSUES. 


104. — Sieve  Tissue.  As  found  in  the  Angiosperms  this 
tissue  is  made  up  of  sieve  ducts  and  the  so-called  latticed 
cells.  The  former  (the  sieve  ducts)  consist  of  soft,  not 
lignified,  colorless 
tubes  of  rather  wide 
diameter,  having  at 
long  intervals  horizon- 
tal or  obliquely  placed 
perforated  septa.  The 
lateral  walls  are  also 
perforated  in  restrict- 
ed areas,  called  sieve 
discs,  and  through 
these  perforations  and 
those  in  the  horizontal 
walls  the  protoplasmic 
contents  of  the  con- 
tiguous cells  freely 
unite  (Figs.  67  and 
68).  In  many  plants 
the  sieve  discs  close  up 
in  winter  by  a  thick- 
ening of  their  sub- 
stance (Fig.  69). 

The  tissue  composed 
of  these  ducts  is  gene- 
rally loose,  and  more 
or  less  intermingled 
with  parenchyma ;  in 
some  cases  even  single 
ducts  run  longitudin- 
ally through  the  sub- 
stance of  other  tissues. 


Fig.  68.— Longitudinal  tangential  section  of  the 


young  bark  of  the  grape  (Wis  tin  if  era),  taker 
the  beginning  of  July.    $,  s,  sieve  tubes,  with  i 


Jll  the   form  described  ti°nsof  the  transverse  plates—  iu  the  left-hand  sie 

.,     .     .          ,  tube,  at  the  top  of  the  figure  a  lateral  plate  is 

It    IS  found  OnlV  shown  ;    »t,  m,  medullary  rays,  with   crystals  in 

»    ,1  "  some  of  the  cells—  between  the  sieve  tabes  them- 

One    Ot    the  COmpO-  selves,  and  between  them  and  the  medullary  rays, 

fa    n-t    +1          1,1    ••  a  e  masses  of  parenchyma  iphloem  purenchyma) 

the    phloem  X  145.-Aftcr]JeBary. 


portion  of  the  fibro-  vascular  bundle. 

105.  —  The  so-called   latticed  cells  ar3  probably  to  be 


80 


BOTANY. 


regarded  as  undeveloped  sieve  ducts,  and  hence  the  tissue 
they  form  may  be  included  under  sieve  tissue.  Latticed 
cells  are  thin-walled  and  elongated  ;  they  differ  from  true  sieve 
ducts  principally  in  being  of  less  diameter,  and  in  having 
the  markings  but  not  the  perforations 
of  sieve  discs.  Both  of  these  differences 
are  such  as  might  be  looked  for  in  un- 
developed sieve  tissue. 

1O6. — In  the  corres- 
ponding parts  of  the  vas- 
cular bundles  of  Gymno- 
sperms  and  Pterido- 
phytes  a  sieve  tissue  is 
found  which  differs 
somewhat  from  that  in 
Angiosperms.  In  Gym- 
nosperms  the  sieve  discs, 
which  are  of  irregular 
outline,  occur  abundant- 
ly upon  the  oblique  ends 
and  radial  faces  of  the 
FigL  69.  -  Longitudinal  broad  tubes  (Fig.  70). 
"Iothe0gfraphe!  In  Pteridopliytes  the 
Ve^niate  *•  tubes  have  varying 
forms ;  in  Equisetum 
After  DC  Ba7yr'  '  an(j  Qphioglossum  they 
are  prismatic,  with  numerous  horizontal  but 
not  vertical  sieve  discs  ;  in  Pteris  and  many 
other  ferns  they  have  pointed  extremities, 
and  are  greatly  elongated,  bearing  the  sieve 
discs  upon  their  sides  (Fig.  71).  In  the 
larger  Lycopodiaccm  the  sieve  tubes  are  pris- 
matic and  of  great  length ;  in  the  smaller 
species  there  are  tissue  elements  destitute  of  P|atf s »repia< 

.  erally  and  are  corn- 

Sieve  discs,  but  which  are  otherwise,  mclud-  posed  of  many  utiie 

...  .        ,,  ,,       ,.,         .,        punctured     areas 

ing    position  in  the    stem,  exactly  like  the  grouped  together  ir- 
sieve  ducts  of  the  larger  species.  A^ei^e'Bary. 

(a)  Good   specimens  of  sieve  tissue  may  be  obtained  for  study  by 
making  longitudinal   sections    of    the  stems  of  Cucurbita,   Cucumis, 


THE  PRINCIPAL    TISSUES. 


81 


Eehinocystis,  Ecbalium,  Vitis,  Bignonin,  and  Calamus  Rotang  ;  also 
Abies  pectinatff,  Larix,  Juniperus,  Sequoia,  and  Ginkgo ;  also  Pteris, 
Osmunda,  Equisetum,  and  Lycopodium. 

(6)  By  making  repeated  horizontal  sections  the  horizontal  sieve  discs 
may  be  found  and  studied. 

(c)  Alcoholic  specimens  afford  much  more  satisfactory  results  than 
fresh  ones  ;  especially  is  this  the  case  with  the  more  succulent  plants. 


Pig.  71. — Sieve  tissue  of  Pteris  aquilina.  A,  end  of  a  sieve  tube  isolated  by  macer- 
ation; B.  portions  of  two  tubes  seen  in  vertical  section ;  in  «'  the  sieve  plates  are 
Keen  in  front  view ;  at  c,  c,  they  are  seen  in  section ;  the  tube  s2  has  sieve  plates 
on  its  right  and  left  walls,  but  none  on  its  further  wall,  which  is  in  contact  with  pa- 
rcnchyma-cdls  ;  two  of  the  latter  are  seen  to  have  nuclei  in  them,  x  375. — After  i)e 
Bary. 


1O7. — Tracheary  Tissue.  Under  this  head  are  to  be 
grouped  those  vessels  which,  while  differing  considerably  in 
the  details,  agree  in  having  thickened  walls,  which  are  perfo- 
rated at  the  places  where  similar  vessels  touch  each  other.  The 


BOTANY. 


thickening,  and  as  a  consequence  the  perforations,  are  of 
various  kinds,  but  generally  there  is  a  tendency  in  the  former 
to  the  production  of  spiral  bands ;  this  is  more  or  less  evident 
even  when  the  bands  form  a  network.  The  transverse  parti- 
tions, which  may  be  horizontal  or  oblique,  are  in  some  cases 
perforated  with  small  openings,  in  others  they  are  almost  or 
entirely  absorbed.  The  diameter  of  the  vessels  is  usually 
considerably  greater  than  that  of  the  surrounding  cells  and 
elements  of  other  tissues,  and  this  alone  in  many  cases  may 
serve  to  distinguish  them.  When  young  they  of  course  con- 
tain protoplasm,  but  as  they  become  older  this  disappears, 
and  they  then  contain  air. 

108. — Tracheary  tissue  is  found  only  in  Pteridophytes 


Fig.  ~2.— Longitudinal  section  of  a  portion  of  the  stem  of  Impatient  Bakumina.  n.  a 
ringed  vessel  :  i/,  a  vessel  with  rings  and  short  spirals  ;  ?;",  a  vessel  with  two  spirals  ; 
v"'  and  v"",  vessels  with  branching  spirals  ;  -t""\  a  vessel  with  irregular  thicken- 
ings, forming  the  reticulated  vessel.— After  Duchartre. 

and  Phanerogams.     The  principal  varieties  of  vessels  found 
in  tracheary  tissues  are  the  following  : 

(1.)  Spiral  Vessels,  which  are  usually  long,  with  fusiform 
extremities  ;  their  walls  are  thickened  in  a  spiral  manner 
with  one  or  more  simple  or  branched  bands  or  fibres  (Fig. 
72,  v",  v'",  v"").  This  form  may  be  regarded  as  the  typical 
form  of  the  vessels  of  tracheary  tissue.  In  most  cases  the 
direction  of  the  spiral  is  from  right  to  left.*  It  is  frequent- 
ly in  one  direction  in  the  earlier  formed  spirals  and  the  op- 

*  Right  to  left,  in  speaking  of  these  spirals,  as  also  in  describing  the 
twining  of  certain  climbing  plants,  is  passing  up  and  around  in  the  di- 
rection of  the  hands  of  a  watch.  Left  to  right  is  of  course  up  and 
nround  opposite  to  the  hands  of  a  watch. 


THE  PRINCIPAL   TISSUES.  89 

posite  in  those  formed  later ;  while  in  interrupted  spirals 
both  directions  occur  in  the  same  vessel.    Ringed  and  reticu- 
lated vessels  are  opposite  modifications  of  the  spiral  form  : 
A 


Fig.  73.— Scalariform  vessels  of  the  rhizoma  of  Pteris  aqtiilina.  A,  longitudinal  sec- 
tion of  an  end  (about  one  third  of  the  whole)  of  a  short  vessel ;/,  the  fusiform  ex- 
tremity, with  long  pits  placed  transversely;  B,  a  small  portion  of  A,  taken  from  x, 
and  much  more  highly  magnified  ;  C\  a  longitudinal  section  of  a  portion  of  the  side 
wall  between  two  vessels  :  D,  a  similar  section  through  the  inclined  end  wall  (A.f) ; 
in  the  upper-part  of  D,  at/  the  wall  between  the  thickening  ridges  is  broken  through. 
A,  X  142  ;  the  others  X  375.-Af  ter  De  Bary. 

the  first  are  due  to  an  under-development  of  the  thickening 
forces  in  the  young  vessels,  resulting  in  the  production  here 
and  there  of  isolated  rings  (Fig.  72,  v) ;  reticulated  vessels 
are  due,  on  the  contrary,  to  an  over-development,  which 


KOTANY. 


gives  rise  to  a  complex  branching  and  anastomosing  of  the 
spirals  (Fig.  72,  v'""). 

(2.)  Scalariform  vessels.  These  are  prismatic  vessels  whose 
walls  are  thickened  in  such  a  way  as  to  form  transverse 
ridges,  as  described  in  paragraph  32,  page  28.  They  are  wide 
in  transverse  diameter  and  their  extremities  are  fusiform  or 
truncate  (Fig.  73). 

(3.)  Pitted  Vessels.  The  walls  of 
these  vessels  are  thickened  in  such  a 
way  as  to  give  rise  to  pits  and  dots, 
as  described  in  paragraph  31,  page 
26.  The  vessels  are  usually  of  wide 
diameter;  in  some  forms  they  are 
crossed  at  frequent  intervals  by  per- 


Fis.  74. 


FIG.  75. 


Fig.  74.— Pitted  vessels  of  Artntolochla  stp'io,  from  a  longitudinal  section  of  the 
stem  ;  the  vessel  on  ihe  right  is  seen  in  section,  that  on  tin-  left  from  without  ;  <i.<i. 
rings,  which  are  remnants  of  the  original  transverse  partitions  ;  b,  b,  sections  of  the 
walls  ;  betwei-n  Ihe  vessels  arc  parenchyma-culls,  hijjhiy  ma^nitted. — After  Duchai  tie. 

Fig.  75 — TracheTdee  of  Cytt»vs  laburnum,  from  a  longitudinal  tti<  <;ential  section 
of  the  stem  ;  m,ra,  a  cross-section  of  a  medullary  ray  ;  in  ihreeof  the  cells  the  pitted 
partitions  are  seen  ;  the  medullnry  ray  is  surrounded  by  traeheldes,  which  are  spi- 
rally marked  and  sparingly  pitted  ;  at  a,  two  tracheldes  have  fused  by  the  breaking 
of  the  wall  ;  *,  #,  slightly  modified  cambium-cells.  X  375.— After De  Bary. 

forated  horizontal  or  inclined  septa  (Fig.   74) ;    in   other 
forms  they  have  fusiform  extremities. 

(4.)  Tracheides.     These  consist  for  the  most  part  of  single 
closed  cells,  or  of  elements  which  closely  resemble  cells; 


THE  PRINCIPAL   TISSUES.  85 

otherwise  they  possess  the  characters  of  vessels.  In  one  form, 
as  in  the  so-called  wood-cells  of  Gymnosperms  (see  paragraph 
30,  page  25)  they  resemble  on  the  one  hand  the  pitted  ves- 
sels, and  on  the  other  the  fibres  of  the  wood  of  Angio- 
sperms.  Every  gradation  between  these  trache'ides  and  the 
other  forms  of  tracheary  tissue  occur.  In  another  form,  as  in 
Cytisus  and  Celtis,  the  trache'ides  are  shorter  than  in  the 
preceding,  quite  regular  in  their  form,  and  with  tapering 
extremities  (Fig.  75).  Their  walls  are  but  slightly  thickened, 
and  are  marked  with  spirals  and  pits.  When  the  wall  be- 
tween two  contiguous  cells  breaks  through  or  becomes  ab- 
sorbed the  close  relation  of  such  trache'ides  to  spiral  vessels 
is  readily  seen. 

Trache'ides  may  be  regarded  as  composing  a  less  differen- 
tiated form  of  tissue,  related  on  the  one  hand  to  true  tra- 
oheary  tissue  and  on  the  other  to  fibrous  tissue. 

(a)  Specimens  of  spiral  vessels  with  the  spirals  passing  from  right 
to  left  may  be  obtained  by  making  longitudinal  sections  of  the  stems 
of  Malva  rotundifolia,  Impatiens  Balsamina.  and  many  other  plants. 
If  the  thin  slicea  are  macerated  in  nitric  acid  and  potassium  chlorate 
the  structure  may  be  studied  to  still  better  advantage.     The  spirals  in 
the  vessels  of  Pinus  sylvextris  pass  from  left  to  right ;  they  may  be 
examined  in  longitudinal  sections  of  the  leaves  or  young  twigs.     The 
stems  of  Vitis  vinifera,  Berberis  milgaris,  Bignonia  capreolctta,  and  Ar- 
temisia abrotanum  furnish   examples   of  vessels,  the  first   formed  of 
which  have  their  spirals  runaing  from  right  to  left  and  the  later  ones 
from  left  to  right.    Interrupted  spirals  showing  the  two  directions  may 
be  found  in  stems  of  Cucurbita. 

(b)  Examples  of  scalariform  vessels  may  be  obtained  with  the  greatest 
ease  from  the  rhizomes  of  ferns — e.g.,  of  Pteris  ;  it  may  also  be  obtained, 
from  many  Dicotyledons — e.g.,  the  stems  of  Vitis. 

(c)  Fine  specimens  of  pitted  vessels  may  be  studied  in  longitudinal 
sections  of  many  kinds  of  wood — e.g.,Pirus,  Quercus,  and  Liriodendron  ; 
among  herbs,  Impatiens  and  Rlcinus  furnish  good  examples. 

(ff)  In  order  to  study  the  trache'ides  of  the  Gymnosperms  thin  slices 
of  the  wood — of  Pinus,  for  example — should  be  heated  for  some  time  in 
nitric  acid,  and  potassium  chlorate.  By  this  means,  after  transferring 
to  a  glass  slide  and  covering  in  the  usual  way,  the  trachei'des  may  be 
easily  isolated  by  gently  tapping  upon  the  cover-glass. 

(e)  Trache'ides  of  the  second  form  are  easily  studied  in  horizontal  and 
longitudinal  sections  of  the  wood  of  (Jeltis. 


BOTANY. 


§  III.    THE  PRIMARY  MERISTEM.* 

109. — Under  this  name  are  grouped  the  unformed  and 
growing  tissues  found  at  the  ends  of  young  stems,  leaves,  and 
roots.  In  these  parts  the  tissues  described  above  (paragraphs 
99  to  108)  have  not  yet  formed ;  they  are,  on  the  contrary, 
composed  entirely  of  a  mass  of  thin-walled,  growing,  and 
dividing  cells  containing  an  abundance  of  non-granular  pro- 
toplasm. In  the  lower  plants  the  meristem-cells  do  not 
change  much  in  their  configuration  or  general  structure  as 
they  develop  into  the  ordinary  plant-cells ;  but  the  higher 
the  type  of  plant,  the  greater  are  the  changes  which  take 
place  during  the  development  of  meristem  into  permanent 
tissues. 

110. — In  most  of  the  plants  outside  of  the  Phanerogams 
the  primary  meristem  is  the  result  of  the  continually  repeated 
division  of  a  single  mother-cell  situated  at  the  apex  of  the 
growing  organ.  In  the  simplest  forms  this  apical  cell  is  the 
terminal  one  of  a  row  of  cells,  as  in  many  algae  and  fungi. 
The  apical  cell,  in  such  cases,  keeps  on  growing  in  length, 
and  at  the  same  time  horizontal  partitions  are  forming  in  its 
proximal  portion.  In  this  way  long  lines  of  cells  may 
originate. 

In  the  more  complicated  cases  the  segments  cut  off  from 
the  apical  cell  grow  and  subdivide  in  different  planes,  so  as 
to  give  rise  to  masses  of  cells.  The  partitions  which  succes- 
sively divide  the  apical  cell  are  sometimes  perpendicular  to 
its  axis,  but  more  frequently  they  are  oblique  to  it.  In  most 
mosses,  for  example  (Fig.  76),  the  apical  cell  is  a  triangular, 
convex-based  pyramid,  whose  apex  is  its  proximal  portion. 
The  successive  segments  are  cut  off  from  the  apical  cell  by 
alternate  partitions  parallel  to  its  sides,  thus  giving  rise  to 
three  longitudinal  rows  of  cells.  Most  Pteridophytes  have 
an  apical  cell  not  much  different  from  that  of  the  ma- 
jority of  mosses.  In  Equisetum,  for  example,  it  is  an  in- 
verted triangular  pyramid,  having  a  convex  base  (Fig.  77  ; 

*  From  tlie  Greek  /if/wS,  part,  and  Tt-pviev,  to  cut  off.  This  tissue  is 
sometimes  called  Proto-meristem. 


PRIMARY  MEHIHTEM.  87 

A,  side  view,  B,  a  section).  The  segments  (daughter-cells) 
are  cut  off  by  alternating  partitions  parallel  to  the  plane 
sides  of  the  pyramid,  as  in  the  mosses.  In  some  of  the 
Bryophytes  and  Pteridophytes  the  apical  cell  is  wedge-shaped 
— i.e.,  with  only  two  surfaces — and  in  such  cases  two  instead 
of  three  rows  of  meristem-cells  are  formed. 

111. — In  the  Phanerogams  the  Primary  Meristem  is  de- 
veloped from  a  group  of  cells,  instead  of  from  a  single  one  ; 
they  therefore  have  no  apical  cell.  This  group  of  cells 


Fig.  76.— Longitudinal  stciioii  of  apt-x  of  stem  of  a  moss  (Fontinalis  antipyretlcri). 
v,  aplcHl  cell,  forming  segments  (3  rows),  each  segment  divided  into  an  outer  cell, 
«,  and  an  imer  one— the  former  develops  cortex  of  the  stem  and  a  leaf,  the  latter 
the  inner  tissue  of  the  stem  ;  z,  apical  cell  of  lateral  leaf-formins;  shoot,  arising 
below  a  leaf  ;  c,  first  cell  of  leaf  ;  6,  cells  forming  cortex.— After  Leitgeb. 

occupies  approximately  the  same  position  in  the  organs  of 
Phanerogams  as  the  apical  cell  docs  in  the  Bryophytes  and 
Pteridophytes ;  it  is  composed  of  cells  which  have  the  power 
of  indefinite  division  and  subdivision. 

112.— The  apical  cell,  and  its  actively  growing  daughter- 
cells  in  its  immediate  vicinity,  or  in  the  case  of  the  Phanero- 
gams the  apical  group  of  cells,  with  their  daughter-cells, 
constitute  the  Growing  Point  or  Vegetative  Point  (Punctum 
vegetationis)  of  the  organ.  When  this  active  portion  is 
conical  in  shape  it  is  the  Vegetative  Cone  of  some  authors. 


88 


BOTANY. 


(a)  Primary  Meristem  tissue  may  be  readily  obtained  for  study  by 
making  thin  longitudinal  sections  of  the  tips  of  growing  shoots  of 
Equixttum,  Phaseolm,  Ilippuris,  and  the  roots  of  Pteris,  Zea,  Impa- 
tiens,  etc.,  or  by  carefully  dissecting  out  the  youngest  rudiments  of  the 
leaves  of  many  Monocotyledons. 

The  value  of  the  specimen  will  often  be  increased  by  staining  it 
with  carmine. 

(ft)  The  apical  cell,  which  may  be  seen  in  the  best  of  the  above-men- 


Fig  77.— The  growing  point  of  (he  stem  of  Eqvisetum  Sfirpoides.  A,  seen  from 
without,  showing  the  apical  cell  at  the  top  ;  the  numerals  1,  3,  4,  etc.,  indicate  the 
order  of  the  formation  of  the  partitions  of  the  apical  cell;  that  marked  1  is  the  last 
formed,  3  the  third  from  the  last,  etc.  :  between  4  and  7  on  the  right,  and  6  and  9  on 
the  left,  are  the  partitions  which  form  after  the  primary  ones;  B,  a  vertical  section  of  A. 

tioned  sections  of  Equisetum  and  Pteris,  should  also  be  studied  by 
making  extremely  thin  cross- sections  of  the  apical  portion  of  the 
Vegetative  Cone  ;  the  triangular  shape  of  the  apical  cell  can  thus  be 
made  out. 

The  simple  side  view  of  the  isolated  Vegetative  Cone  is  also  instruc- 
tive when  so  prepared  that  it  can  be  rotated  under  the  microscope. 


CHAPTER  VII. 

TISSUE   SYSTEMS. 
§  I. — THE  DIFFERENTIATION  OF  TISSUES  INTO  SYSTEMS. 

113. — It  rarely  happens  that  the  tissues  which  compose 
the  body  of  a  plant  are  uniform.  In  the  great  majority  of 
cases  the  cells  of  the  Primary  Meristem  become  differently 
modified,  so  as  to  give  rise  to  several  kinds  of  tissues.  The 
outer  cells  of  the  plant  become  more  or  less  modified  into  a 
boundary  tissue,  and  the  degree  of  modification  has  relation 
to  its  environment.  Certain  inner  cells,  or  lines  of  cells,  be- 
come modified  into  sclerenchyma,  or  some  other  supporting 
tissue  (collenchyma,  or  fibrous  tissue),  and  here  again  there 
is  a  manifest  relation  to  the  environment  of  the  plant.  Cer- 
tain other  inner  cells,  or  rows  of  cells,  become  modified  into 
tubes  affording  a  ready  means  for  conduction,  and  appear  to 
have  a  relation  to  the  physical  dissociation  of  the  organs  of 
the  higher  plants,  in  which  only  they  occur.  Thus,  in  phy- 
siological terms,  there  may  be  a  boundary  tissue,  a  support- 
ing tissue,  and  a  conducting  tissue,  lying  in  the  mass  of  less 
differentiated  ground  tissue. 

114. — In  different  groups  of  plants  the  elementary  tissues 
described  in  previous  paragraphs  (99  to  108)  are  aggregated 
in  different  ways,  and  are  variously  modified  to  form  these 
bounding,  supporting,  and  conducting  parts  of  the  plant. 
Several  tissues,  or  varieties  of  tissue,  are  regularly  united  or 
aggregated  in  particular  ways  in  each  plant,  constituting 
what  may  be  called  Groups  or  Systems  of  Tissues.  A  Tis- 
sue System  may  then  be  described  as  an  aggregation  of  ele- 
mentary tissues,  forming  a  definite  portion  of  the  internal 
structure  of  the  plant.  From  what  has  already  been  said,  it 


90  BOTANT. 

is  clear  that  systems  of  tissue  do  not  exist  in  the  lowest 
plants,  and  that  they  reach  their  fullest  development  only 
in  the  highest  orders.  It  is  evident  also  that  these  systems 
have  no  existence  in  the  youngest  parts  of  plants,  but  that 
they  result  from  a  subsequent  development. 

115. — Many  systems  of  tissue  might  be  enumerated  and 
described  ;  but  here  again,  as  with  the  elementary  tissues, 
while  there  are  many  variations,  there  are  also  many  grada- 
tions, having  on  the  one  hand  a  tendency  to  give  us  a  long 
list  of  special  forms,  and  on  the  other  to  reduce  them  to  one, 
or  at  most  to  two  or  three.  The  three  systems  proposed 
by  Sachs  are  instructive,  and  will  be  followed  here  ;  they 
are :  (1)  the  Fundamental  System,  which  includes  the  mass 
of  unmodified  or  slightly  modified  tissues  found  in  greater  or 
less  abundance  in  all  plants  (except  the  lowest)  ;  (2)  the 
Epidermal  System,  composed  mainly  of  the  boundary  cells 
and  their  appendages  (hairs,  scales,  stomata,  etc.)  ;  (3)  the 
Fibro-vascular  System,  comprising  those  varying  aggrega- 
tions of  tissues  which  make  up  the  string-like  masses  found 
in  the  organs  of  the  higher  plants. 

§  II. — THE  EPIDERMAL  SYSTEM  OF  TISSUES. 

116 — This  is  the  simplest  tissue  system,  as  it  is  the  ear- 
liest to  make  its  appearance,  in  passing  from  the  lower  forms 
to  the  higher.  It  is  also  (in  general)  the  first  to  appear  in 
the  individual  development  of  the  plant.  It  is  sometimes 
scarcely  to  be  separated  from  the  underlying  mass,  as  in 
most  higher  Thallophytes  and  Bryophytes  ;  and  here  it  is 
composed  of  but  one  tissue — parenchyma — or  of  two  or  more 
slight  variations  of  it.  In  Pteridophytes  and  Phanerogams. 
while  it  may  be  very  simple  in  some  (aquatic)  plants,  it  fre- 
quently attains  some  degree  of  complexity,  and  is  sharply 
separated  from  the  underlying  ground  tissues. 

117. — In  the  simpler  epidermal  structures  of  the  Thallo- 
phytes the  cells  are  generally  darker  colored,  smaller,  and 
more  closely  approximated  than  they  are  in  the  subjacent 
mass  ;  in  some  higher  fungi  a  boundary  tissue  may  be  easily 
separated  as  a  thickish  sheet,  but  probably  in  such  case  a 


THE  EPIDERMAL  SYSTEM.  91 

portion  of  the  underlying  mass  is  also  removed.  In  many 
of  the  Thallophytes  there  is  absolutely  no  differentiation  of 
an  epidermal  portion. 

118. — In  the  Bryophytes  there  is  in  general  a  poor  epider- 
mal development  ;  it  is  composed  for  the  most  part  of  one 
or  more  weakly  defined  layers  of  smaller  cells,  which,  how- 
ever, pass  by  insensible  gradations  into  the  inner  tissue 
mass.  Here,  however,  the  first  true  epidermal  hairs  make 
their  appearance. 

119. — In  one  group  of  the  Liverworts — the  Marchantiacem 


Fig.  78.— Longitudinal  section  of  erect  portion  of  thallus  of  Marchantia  pnlymor- 
1>ha.  o,  epidermis  ;  8,  walls  beiween  air-spaces,  the  latter  filled  with  rows  of  chloro- 
phyll-bearing cells,  chl ;  sp,  a  stoina  ;  y,  a  large  parenchyma-cell.  X  550. — After  Sachs. 

— there  is  an  epidermal  system  of  a  high  degree  of  perfection, 
and  composed  of  epidermis  proper  and  stomata  (Fig.  78). 
The  epidermis  consists  of  a  single  layer  of  somewhat  tabu- 
lar cells  arching  over  the  air-cavities  which  occupy  the  upper 
surface  of  the  plants  ;  it  is  perforated  here  and  there  by  sto- 
mata or  breathing  pores,  composed  of  four  to  eight  circular 
rows  of  cells  placed  one  above  the  other  (sp  in  the  figure). 
These  chimney-like  structures  originate  by  the  division  of  a 
single  cell  into  four  or  six  radiating  daughter-cells  ;  in  the 
centre  of  this  group  an  intercellular  pore  is  formed  by  the 
lateral  growth  of  the  cells  (Fig.  79)  ;  and  by  a  subsequent 


92  BOTANY. 

horizontal  division  the  several  superimposed  circular  rows 
of  cells  are  formed. 

120. — In  true  mosses  the  sporangia  possess  an  epidermal 
system  which  is  composed  of  a  layer  of  strongly  cuticular- 
ized  cells — the  epidermis — sometimes  provided  with  stomata. 
Other  portions  of  the  plant,  aside  from  the  sporangia,  are 
destitute  of  a  true  epidermis  or  of  stornata. 

121. — The  epidermal  systems  of  Pteridophytes  and  Phaner- 
ogams are  so  much  alike  that  they  may  be  described  together, 
although  it  must  be  remembered  that  in  the  latter  group 
they  are,  in  general,  somewhat  more  perfect  than  in  the  for- 
mer.  In  these  groups  the  epidermal 
structures  consist  usually  of  three  por- 
tions :  (1)  a  layer  of  more  or  less 
modified  parenchyma — the  epidermis 
proper — bearing  two  other  kinds  of 
structures  which  develop  from  it,  viz., 
(2)  trichomes,  and  (3)  stomata. 

122.— Epidermis.  The  differentia- 
tion of  parenchyma  in  the  formation 
of  epidermis,  when  carried  to  its  ut- 
most extent,  involves  three  different 
modifications  of  the  cells,  viz.,  (1) 
change  of  form,  (2)  thickening  of  the 
&**?%**$£%£  walls,  (3)  disappearance  of  the  proto- 
reSgmthTarge?;  plasmic  contents.  These  three  modi- 
a,  guard-ceils  —After  Sachs,  fications  may  occur  in  varying  de- 
grees of  intensity  ;  they  may  all  be  slight,  as  in  many  aquatic 
plants  and  in  the  young  roots  of  ordinary  plants  ;  or  the  cells 
may  change  their  form,  while  there  may  be  little  thickening 
of  their  walls,  as  in  other  aquatic  plants,  and  some  land  plants 
which  live  in  damp  and  shady  places  ;  or  on  the  other  hand, 
the  change  of  form  of  the  cells  may  be  but  little,  while 
their  walls  may  have  greatly  thickened,  resulting  in  a  disap- 
pearance of  their  protoplasm,  as  may  be  seen  in  parts  of 
some  land  plants  which  grow  slowly  and  uniformly.  When 
the  differentiation  of  epidermis  is  considerable,  it  can  usu- 
ally be  readily  removed  as  a  thin  transparent  sheet  of  color- 
less cells, 


TUB,  EPIDERMAL  SYSTEM.  93 

123. — The  change  in  the  form  of  the  epidermal  cells  is 
due  to  the  mode  of  growth  of  the  organ  of  which  they  form 
a  part;  the  lateral  and  longitudinal  growth  of  an  organ 
causes  a  corresponding  extension  and  consequent  flattening 
of  the  cells  ;  if  the  growth  has  been  mainly  in  one  direction, 
as  in  the  leaves  of  many  Monocotyledons,  and  the  young 
shoots  of  many  Dicotyledons,  or  if  the  growth  in  two  direc- 
tions has  been  regular  and  uniform,  as  in  the  leaves  of  some 
Dicotyledons,  the  cells  are  quite  regular  in  outline ;  where, 
however,  the  growth  is  not  uniform  the  cells  become  irregu- 
lar, often  extremely  so  (Fig.  89,  page  100). 

124. — The  thickening  of  the  walls  is  greatest  in  those 
plants  and  parts  of  plants  which  are  most  exposed  to  the  dry- 
ing effects  of  the  atmospheie.  It  consists  of  a  thickening  of 
the  outer  walls,  and  frequently  of  the  lateral  ones  also.  The 
outer  portion  of  the  thickened  walls  is  cuticularized,  and 
this,  by  a  subsequent  stratification  and  lamellation,  is  separ- 
ated as  a  continuous  pellicle,  the  so-called  cuticle. 

125. — The  cuticle  extends  uninterruptedly  over  the  cells, 
and  maybe  readily  distinguished  from  the  other  portions 
of  the  outer  epidermal  walls.  It  is  insoluble  in  concen- 
trated sulphuric  acid,  but  may  be  dissolved  in  boiling 
caustic  potash.  Treated  with  iodine  it  turns  a  yellow  or 
yellowish  brown  color.  A  waxy  or  resinous  matter  is  fre- 
quently developed  upon  the  surface  of  the  cuticle,  constitut- 
ing what  is  called  the  Uoom  of  some  leaves  and  fruits.  De 
Bary*  distinguishes  four  kinds  of  waxy  coating,  as  follows  : 
(1)  continuous  layers  or  incrustations  of  wax — e.g.,  on  the 
leaves  and  stems  of  purslane,  the  leaves  of  Fuchsia,  yew,  the 
stems  of  the  wax  palms  (Ceroxylon],  etc.  ;  (2)  coatings  com- 
posed of  multitudes  of  minute  rods  placed  vertically  side  by 
side  upon  the  cuticle — e.g.,  on  the  stems  of  sugar  cane, 
Coix  lachryma,  and  some  other  grasses ;  (3)  coatings  made 
up  of  minute  rounded  grains  in  a  single  layer — e.g.,  on  the 
leaves  of  the  cabbage,  onion,  tulip,  clove-pink  (Dianthus 


*  "  Vergleichende  Anatomic  der  Vegetationsorgane  der  Phaneroga- 
men  und  Fame,"  1877,  p.  87,  where  figures  of  several  of  these  kinds 
are  given. 


94  BOTANT. 

Caryophyllus),  etc. ;  (4)  coatings  of  minute  needles  or  grains 
irregularly  covering  the  surface  with  several  layers — e.g.,  on 
the  leaves  of  Eucalyptus  globulus,  rye,  etc. 

126.— The  protoplasm  of  the  epidermal  cells  generally 
disappears  in  those  cases  where  there  is  much  thickening  of 
the  walls  ;  it  is  always  present  in  young  plants  and  parts  of 
plants  ;  it  is  also  frequently  present  in  older  portions,  which 
are  not  so  much  exposed  to  the  drying  action  of  the  atmos- 
phere, as  in  roots,  and  the  leaves  and  shoots  of  aquatic  plants, 
and  of  those  growing  in  humid  places.  In  few  cases,  how- 
ever, are  granular  protoplasmic  bodies  (e.g.,  chlorophyll)  pres- 
ent in  epidermal  cells.* 

127. — AVhile  the  epidermis  always  consists  at  first  of  but 
one  layer  of  cells,  it  may  become  split  into  two  or  more  lay- 
ers by  subsequent  divisions  parallel  to  its  surface.  These 
layers  may  resemble  the  outer  one  and  have  their  walls 
thickened,  as  in  the  leaves  of  the  Oleander,  or  they  may  con- 
sist of  thin-walled  cells  with  watery  contents  (constituting 
the  so-called  Aqueous  Tissue),  as  in  the  leaves  of  Ficus  and 
Begonia. 

(a)  Epidermis  may  be  studied  with  comparatively  little  difficulty. 
In  many  cases  it  may  be  stripped  off  in  thin  sheets  and  mounted  in 
the  usual  way ;  such  preparations,  with  thin  cross-sections  (which  are 
readily  made  by  placing  a  piece  of  leaf  between  pieces  of  elder  pith), 
are  sufficient,  in  most  cases,  to  give  a  good  knowledge  of  the  structure. 
The  leaves  of  many  Liliacfce  (hyacinths,  lilies,  etc.)  and  Graminece  may 
be  examined  for  regular  cells,  and  those  of  many  Dicotyledons,  as  bal- 
sams, primroses,  and  fuchsias,  for  irregular  ones. 

(6)  Thickened  epidermal  walls  may  be  found  in  leaves  of  a  hard  tex- 
ture, as  those  of  the  pines,  holly,  oleander,  mistletoe,  many  Composite, 
and  in  the  stems  of  many  Cactace.ce.  The  stratification  of  the  thickened 
walls  may  be  brought  out  in  the  cross-sections  by  heating  in  a  solution 
of  potash. 

(r)  A  series  of  specimens  of  the  epidermis,  taken  from  leaves  of  all 
ajjes.from  their  youngest  and  smallest  rudiments  in  the  bud  up  to  full- 
grown  ones,  is  instructive. 


*  In  the  leaves  of  Primula  sinen&is,  grown  in  the  green-house,  the 
epidermal  cells  contain  many  chlorophyll-bodies  ;  the  leaves  of  Fuchsias, 
under  similar  conditions,  possess  a  few  chlorophyll-bodies  in  the  epider- 
mal layer. 


THE  EPIDERMAL  SYSTEM. 


95 


128.— Trichomes.  Under  this  term  are  to  be  included  the 
outgrowths  which  arise  from  the  epidermis  ;  they  may  have 
the  form  of  hairs,  scales,  glands,  bristles,  prickles,  etc.,  and 
may  be  composed  of  single  cells,  or  of  masses  of  cells. 

They  originate  mostly  from  the  growth  of  single  epidermal 
cells,*  and  on  their  first  appearance  consist  of  slightly  en- 


FIQ.  81. 


Fia.80. 

Pig.  80. — Transverse  section  of  epidermis  and  underlying  tissue  of  ovary  of  Cu- 
cwtota.  a,  hair  of  a  row  of  cells  ;  b  and  d,  glandular  hairs  of  different  ages ;  «,/, 
c,  hairs  in  the  youngest  stages  of  their  development.  X  100.— After  Prantl. 

Fig.  81  —A  seedling  mustard  plant  with  its  single  root  clothed  with  root -hairs  ; 
the  newest  (lowermost)  portion  of  the  root  is  not  yet  provided  with  root-hairs. 

larged  and  protruding  cells  (Fig.  80,  e,  f,  c).  These  may 
elongate  and  form  single-celled  hairs,  which  may  be  simple 
or  variously  branched.  The  most  important  of  these  hairs 
are  those  which  clothe  so  abundantly  the  young  roots  of  most 
of  the  higher  plants,  and  to  which  the  name  of  Root-hairs 

*  It  is  probable  that  the  common  statement  that  trichomes  al  ways 
develop  from  single  cells  must  be  modified. 


96 


&OTANY. 


has  been  applied  (Fig.  81).  These  are  composed  of  single 
cells,  which  have  very  thin  and  delicate  walls  (Fig.  82),  and 
are  the  active  agents  in  the  absorption  of  nutritive  matters 
for  the  plant. 


i 

Fig.  82.  -Root-hairs  of  a  seedling  rye  plant.  A,  the  ends  of  three  haire,  one  much 
cinallcr  th  in  the  others  ;  the  larger  ones  have  particles  of  sand  adhering  to  and  im- 
bedded in  their  walls  ;  £,  the  base  of  a  hair  growing  from  the  root-cell,  r.  X  900. 


129. — In  the  development  of  the  hairs  on  aerial  parts  of 
plants  it  frequently  happens  that  the  terminal  cell  becomes 
changed  into  a  secreting  cell,  in  which  gummy,  resinous,  or 
other  substances  are  produced  ;  sometimes  several  terminal 


THE  EPIDERMAL   SX8TMH. 


cells  are  so  transformed  into  a  secreting  organ, 
tion  appears  as  a  rounded 
pustule,  partly  surround- 
ing the  secreting  cell 
(Figs.  83  to  87),  and 
which  is  removed  upon 
the  slightest  touch.  Tri- 
chomes  of  this  nature  are 
called  glandular  hairs ; 
they  are  exceedingly  vari- 
able in  form,  and  are  not 
infrequently  short  and 
depressed,  when  they  are 
known  as  surface  glands, 
or  glandular  scales  (Fig. 
87). 


The  secre- 


—  Glandular  hairs  from  the  petiole  of 
o,  sinensit,  in  several  stages  of  deyelop- 


(ft\  Triehomes  are    in  p-ene     ment.   a,  the  beginning  of  the  secretion  iu  the 
•  are,  in  gene-    termina,  ce]1.  b  hair  £ith  a  j         mags  of  ge. 

ral,    easy    objects    of    study,    creted  matter  ;  d,  an  old  hair  after  the  removal 
In  many  cases  they  may  be    of  the  secreted  matter,    x  142.-After  De  Bary. 

simply  scraped  off  and  mounted  in  alcohol,  or  in  a  solution  of  potash 


FIG.  84. 


FIG.  85. 


FIG.  86. 


FIG.  87. 


Fig.  84.  -a',  the  cell  a  of  Fig.  83  more  highly  magnified  ;  a"  the  same  after  removal 
of  the  secretion  by  treatment  with  alcohol,  x  87.5. — After  De  Bary. 

Fig.  85  —  c,  end  of  a  hair  with  large  mass  of  secreted  matter  ;  c',  the  same  after 
treatment  with  alcohol,  x  375.— After  De  Bary. 


Fig.  8(5.— The  end  of  the  hair  (I,  in  Fig.  83.  more  highly  magnified,  showing  the  frag- 
ments of  the  secretion  pustule  surrounding  the  terminal  cell,  which  still  contains  pro- 
topjasm  X  375 — After  De  Bary. 


Fig.  87. — Glandular  scale  from  the  hop.  A,  in  its  young  stage  ;  B,  the  same  some 
time  afterward— the  secretion  from  the  cells  has  pushed  out  the  cuticle  and  filled  the 
space  between  it  and  tho  cell*  (in  the  specimen  from  which  these  were  drawn  the 
secretion  was  removed  by  solution  in  alcohol).  X  142.— After  De  Bary. 

after  wetting  them  with  alcohol  to  free  them  from  entangled  and  en- 
closed air. 


BOTANY. 


(b)  One-celled  simple  hairs  may  be  obtained  from    the  vegetative 
organs  of  species  of  (EnotJiera  and  Brassica  and  many  grasses — e.g., 
species  of  Panicum — and  from  the  seeds  of  the  cotton  plant ;  the  last 
constitute  the  ' '  cotton"  of  commerce. 

(c)  Many-celled  simple  hairs  occur  on  the  filaments  of  Tradescantia, 
on  leaves  of  the  Primrose,  Ageratum,  Erigeron  Canadense,  pumpkin, 
and  very  many  others. 

(d)  Branched  one-celled  hairs  occur  in  Capsclla,  Draba,  Sisymbryum, 
Alyssum,  and  many  other  Cruciferw. 

(e)  Branched  many-celled  hairs  may  be  found  on  the  Mullein  and 
Ivy. 


Vis-  88.— Hairs  from  Thistle  (Otiicus  altiitsimiix).  j,  young  hniir  from  the  stem 
before  it  has  been  drawn  out ;  S,  an  older  hair  more  highly  magnified,  after  its  ex- 
tremity has  been  drawn  out  into  a  thread-like  la*h  ;  C,  hair  with  a  long  laeh  from 
i he  underside  of  a  full-grown  leaf.  Highly  magnified.— After  Heal. 

(/)  Clustered  or  tufted  hairs  are  found  on  many  Malvacew,  and  the 
nearly  related  scales  or  peltate  hairs  on  SJicpherdia. 

((/)  Root-hairs  are  btst  obtained  for  study  by  growing  seeds  of  mustard, 
radish,  wheat,  etc.,  on  damp  cotton  or  blotting-paper,  and  then  mak- 
ing careful  longitudinal  sections  of  the  terminal  portion  of  the  root  at 
the  place  where  the  hairs  are  just  appearing  (usually  several  millimetres 
above  the  tip  of  the  root).  By  making  preparations  in  this  way  all 
stages  of  the  development  of  these  hairs  may  be  studied  in  the  same 
specimen. 

(h)  Glandular  hairs  are  found  in  many  groups  of  plants  ;  they  may 
be  studied  in  Petunia,  Verbena,  Primula,  Martynia,  and  the  tomato. 

(i)  Apparently  related  to  glandular  hairs  are  the  curious  hairs  from 


THE  EPIDERMAL  SYSTEM.  99 

which,  as  pointed  out  by  Professor  Beal,*  are  drawn  out  the  long 
thread-like  lashed  which  are  so  abundant  on  the  leaves  of  some  thistles 
and  other  Composite  (Fig.  88).  These  lashes  appear  to  be  of  the  na- 
ture of  secretions,  and  they  are  capable  of  being  drawn  out  to  an  aston- 
ishing length.  These  are,  in  turn,  much  like  the  glandular  hairs  on 
the  leaves  of  Dipsacm  sylvestris,  discovered  by  Francis  L>arwin,f 
and  from  which  motile  protoplasmic  filaments  protrude.  Mr.  Darwin 
concludes  that  they  have  the  power  of  absorbing  nitrogenous  matter. 

130. — Stomata  (singular,  Stoma).  These  structures  con- 
sist, in  most  cases,  of  two  specially  modified  chlorophyll- 
bearing  cells,  called  the  Guard-cells,  which  have  between 
them  a  cleft  or  slit  passing  through  the  epidermis  (Figs.  89, 
90).  These  openings  are  always  placed  directly  over  interior 
intercellular  spaces.  Stomata  are  developed  from,  and  in 
their  distribution  always  have  a  relation  to,  the  epidermal 
cells;  in  an  epidermis  composed  of  regular  cells  there  is 
more  or  less  regularity  in  the  arrangement  of  the  stomata  ; 
but  when  the  epidermal  cells  are  irregular  the  stomata  are 
also  irregularly  placed. 

They  occur  on  aerial  leaves  and  stems  most  abundantly, 
being  sometimes  exceedingly  numerous,  and  are  exception- 
ally found  on  other  parts,  as  the  sepals,  petals,  and  carpels 
of  the  flowers.  On  submerged  or  underground  stems  and 
leaves  they  are  found  in  less  numbers,  and  from  true  roots 
they  are  always  absent.  The  stomata  on  leaves  are  generally 
confined  to  the  lower  surface,  and  when  present  on  the  up- 
per they  are  usually  much  fewer  in  number  ;  there  are,  how- 
ever, some  exceptions  to  this. 

131. — Their  development  generally  takes  place  in  the  fol- 
lowing way  :  in  a  young  epidermis-cell  a  partition  forms  at 
right  angles  to  the  plane  of  the  epidermis,  cutting  off  a  por- 
tion of  the  cell ;  this  in  one  series  of  cases  becomes  the 
mother-cell  of  the  stoma ;  in  another  series  of  cases,  how- 
ever, it  is  divided  one  or  more  times  by  subsequent  partitions 
before  the  mother-cell  is  formed.  In  either  case,  when  once 

*  In  an  article  entitled  "  How  Thistles  Spin,"  in  the  American  Nat- 
uralist, 1878,  page  643.  See  also  an  article  by  the  same  writer  on 
'  Hairs  and  Glandular  Hairs  of  Plants  :  their  Forms  and  Uses,"  in  the 
same  volume  of  the  journal  named,  on  page  271. 

f  See  his  account,  with  a  plate,  in  Qr.  Jour,  of  Mlc.  Science,  1877,  p.  245. 


100 


BOTANY. 


the  mother-cell    is  formed  a    median  partition- wall  forms 

in  it,  and  gradually  becomes  separated  into  two  plates,  which 

eventually  sepa- 
rate  and  form  a 
pore  through 
the  epidermis. 
The  two  halves  of 
the  mother-cell  be- 
come symmetrical- 
ly rounded  off  into 
semilunar  or  semi- 
circular forms, 
and  constitute  the 
guard-cells  before 
mentioned.  The 
details  of  the  fore- 
going process  in 
one  of  its  more 
complex  forms 
are  illustrated  in 
Fig.  91,  A  and  B. 
The  splitting  of 

the  middle  partition-wall  of  the  mother-cell  is  shown  in  the 

successive  sections  (Fig.  92). 

132. — In  the  light,  under  certain  conditions  of  moisture 

and  temperature,   the 

guard-cells     become 

curved  away  from  each 

other  in  their  central 

portions,  thus  opening 

the   slit  and  allowing 

free    communication 

between  the    external 

air  and  that  in  the  in- 

,         Fig.  90.—  Double  *tomata  from  the  under  surface 
tercellular    Spaces    and     of  the  leaf  ol 'Echlnocystls  lobata.     xSOO.-Fromi 

passages  of  the  leaf. 


Fig.  89.— Stomata  from  the  under  surface  of  the  leaf  of 
Echmocystis  lobata.  s,  s.  stomata  ;  g,  g,  irregular  epider- 
mis-cells between  the  veins  of  the  leaf ;  v,  elongated  and 
regular  epidermis-cells  over  a  vein.  X  250.— From  a 
drawing  by  J.  C.  Arthur. 


drawing  by  J.  C.  Arthur. 


(a)  A  superficial  examination  of  stomata  may  be  easily  made  by 
stripping  off  the  epidermis,  and  mounting  it  in  water  or  alcohol.  Good 
sections  of  stomata  are  more  difficult  to  make  ;  they  may  be  obtained, 


Tig.  91.— The  development  of  the  ftomata  of  the  leaf  of  Sedum  purpurasctm.  A , 
a  piece  of  very  young  epidermis,  showing  the  early  stages  of  tlie  process.  The  nu- 
merals indicate  the  order  of  formation  of  the  partitions  ;  that  marked  1, 1,  1,  was 
formed  first,  then  2,  2,  and  last  3,  3 ;  the  cell  enclosed  by  thesie  three  partitions  is  the 
stoma-mother-cell ;  B.  a  fully  completed  stoma ;  e,  e,  two  original  epidermis-cells— 
in  the  right  hand  one  the  new  partition  1,  1,  1.  first  appeared  ;  this  was  followed  by 
i,  S.  2,  then  by  3,  3,  and  4,  4  ;  ".asily  tho  cell  thus  formed  bee  >me  divided  l>y  a  middle 
partition,  which  Boon  split,  and  thus  formed  the  opening  of  the  stoma.— After  Sachs. 


FIG.  92i).  FIG.  92n. 

Fig.  92. — Development  of  thestomata  of  the  leaf  of  Hyacinthu*  orientalls,  seen  in 
transverse  section.  A,  the  division  of  the  mother-cell  S;  e,  e,  epidermis-cells  ;  p,  », 
parenchyma-cells  ;  i,  small  intercellular  -pace  ;  B  and  C,  the  sanie  a  little  later  ;  i», 
first  separation  of  the  two  guard-cells  by  the  splitting  of  the  partition  between  them, 
forming  the  opening  t  ;  E,  the  fully  formed  stoma.  x  800. — After  Sachs. 


102 


BOTANY. 


however,  by  making  a  large  number  of  very  thin  sections  of  the  whole 
leaf  (by  placing  it  between  two  pieces  of  elder  pith),  when  it  will  be 
found  that  in  some  cases  stomata  have  been  cut  through  in  the  man- 
ner shown  in  Fig.  92. 

(6)  Examples  may  be  obtained  from  any  of  the  higher  plants,  but 
those  which  are  of  a  firm  texture  and  have  a  smooth  epidermis  are 
best  to  begin  with — e.g.,  the  hyacinth,  tulip,  the  lilies,  many  grasses, 
fuchsia,  lilac,  etc. 

(c)  Weiss*  determined  the  number  of  stomata  on  the  epidermis  of 
both  surfaces  of  167  leaves  of  plants  ;  some  of  his  results  are  given 
below: 


In  one  square  millimetre. 

In  one  square  inch. 

Upper  side.'  Under  side. 

Upper  side.  Under  side. 

0 
0 
0 
0 
0 
175 
138 
0 
55 
60 
0 
0 
0 
0 
101 
0 
0 
67 
114 
0 
94 
184 
0 
0 
89 
50 
0 
0 
65 
48 

625 
477 
461 
386 
380 
325 
302 
278 
270 
263 
259 
251 
237 
229 
216 
208 
204 
191 
189 
166 
158 
156 
145 
145 
131 
71 
67 
62 
58 
27 

0 
0 
0 
0 
0 
112,875 
88,910 
0 
35,475 
38,700 
0 
0 
0 
0 
65,145 
0 
0 
43,215 
73,530 
0 
60,630 
118,680 
0 
0 
57,405 
32,250 
0 
0 
41,925 
30.960 

403,125 
308,665 
298,345 
248,970 
212,850 
209,625 
194,790 
179,310 
174,150 
169,635 
167,055 
161,895 
152,865 
147.705 
139,320 
134,160 
131,580 
123,195 
121,905 
107,070 
101,910 
100,620 
93,525 
93,525 
84,495 
45,895 
43,215 
39,990 
38,410 
17.415 

Ailanthus  glandulosa  
Syringa  vulgaris  
Helianthus  annuus 

Brassica  oleracea  
Platanus  occidentalis  
Populus  dilatata  
Solanum  dulcamara  

Euphorbia  cypurissias  
Maclura  aurantinca  

Betula  alba 

Berberis  vulgaris  

Buxus  sempervirens  

Asclepias  incarnata  

Taxus  baccata 

Zea  inais 

Chenopodium  ambrosioides.  . 
Ficus  elastica            

Ribes  aureum          

Populus  monilifera  

Pinus  sylvestris  ,  

Anemone  nemorosa  
1  /i  1  in  in  bulbiferum  

Iris  Germanica  
A  vena  sativa.  .  . 

*Ia  a  paper  on  the  Number  and  Size  of    Stomata,  published    in 
Pringsheim's  "  Jahrbucher  fur  Wissenschaftliche  Botanik,"  1865. 


THE  EPIDERMAL  SYSTEM. 


10:5 


(d)  In  the  plants  he  examined  he  found  that  there  were 


54  species  with  from     1  to  100  stomata  per  sq.  mm. 


100  to  200 

aootoaoo 
300  to  400 

400  to  500 
500  to  600 
600  to  700 


=        645  to    64.500  per  sq.  inch 

=    64,000  to  129,01)0      " 

=  129,000  to  193,500   " 

=  193,500  to  258,000   " 

=  258,000  to  322,500   "    " 


=  387,000  to  451,500 


(e)  Morren's  measurements*  vary  somewhat  from  those  given  by 
Weiss.  The  following,  not  given  by  Weiss,  are  taken  from  Morren's 
table: 


In  one  square  millimetre.      In  one  square  inch. 


Upper  side. 

Under  side.  Upper  side.junder  side. 

Trifolium  pratense  
Humulus  Lupulus  

207 
0 
0 
0 
0 
0 
75 
0 
0 
49 

385 
256 
253 
246 
196 
155 
115 
91 
86 
42 

133,515 
0 
0 
0 
0 
0 
48,375 
0 
0 
31,605 

216,075 
165,120 
163,185 
158,670 
126,420 
99,975 
74.175 
58,695 
55,470 
27,090 

Vitis  vinifera 

Pirus  communis  
Philadelphus  coronarius  
Secale  cereale  

(/)  The  stomata  of  the  so-called  Compass  Plant  (SUphium  lacinia- 
tum)  are  nearly  equal  in  number  on  the  two  sides  of  the  vertical  leaves  ; 
there  are  on  the  true  upper  surface  82  per  sq.  mm.  (=  52,700  per  sq. 
inch),  and  on  the  under  surface,  87  per  sq.  mm.  (=  57,300  per  sq. 
inch).f 

(g)  On  most  leaves  the  Btomata  are  not  distributed  equally  over  all 
portions  of  either  surface  ;  they  are  not  found  on  the  veins,  but  are 
restricted  to  the  areas  between  them.  In  some  plants  this  restriction 
is  accompanied  by  a  further  modification,  as  in  Geanothus  prostratus, 
where  the  stomata  are  confined  to  the  bottoms  of  sunken  pits  which 
occur  on  the  under  side  of  the  leaves.  In  the  long  harsh  leaves  of 
Stipa  spartea  the  stnmata  of  the  upper  surface  are  restricted  to  the 
sides  of  the  deep  longitudinal  channels  which  lie  between  the  promi- 
nent nerves.  (See  Figs.  135-6,  pa<je  158.) 


*  Published  first  in  Bul'etin  de  V Academic  royale  de  Bdgique,  vol. 
16,  number  12,  1864,  and  also  in  part  in  Pringshehn's  "  Jahrbiicher," 
etc..  1.  c. 

f  See  an  article  in  American  Xaturalist,  1877,  p.  486  :  "  Observations 
on  Silphium  laciniatum,  the  so-called  Compass  Plant,"  by  C.  E.  Bessey. 


104 


BOTANY. 


(h)  Water-pores.  De  Bary*  describes  under  this  name  Borne  curious 
stoma-like  structures  which  occur  on  many  plants.  These,  instead  of 
containing  air  in  their  cavities,  normally  contain  water.  Their  guard- 
cells,  which  are,  in  some  cases  at  least,  much  like  those  of  ordinary 
stomata,  are  immovable,  and  as  a  consequence  the  pore  is  incapable  of 
enlargement  or  contraction.  They  are  always  found  over  the  ends  of 
small  bundles  of  spiral  vessels,  which  appear  to  pass  into  the  pore  cav- 
ities. 

One  form  of  these  may  be  readily  examined  in  the  leaves  of  the  f  uch- 


Fio.  93. 


FIG.  94. 


Fig.  93. — Surface  view  of  the  water-pore  on  the  extremity  of  the  leaf-tooth  of  Fuch- 
sia, globofd.  X  500. — After  Arthur. 

Fig.  94.— Transverse  section  of  leaf-tooth  of  Fttctutia  globosa  ;  cp,  chlorophyll- 
bearing  parenchyma,  within  which  is  the  nbro-vascular  bundle ;  ra,  raphis-cells.  x 
125.— Alter  Arthur. 

sia,  and  the  primrose  (Prirmdfi  sinensit).  In  the  fuchsia  they  are  found 
in  the  papillae  or  small  teeth  on  the  margins  of  the  leaves,  and  in  the 
primrose,  in  the  papillae  terminating  the  lobes  and  lobules.  In  Fuclixia 
globosa  each  leaf -tooth  is  provided  with  a  single  terminal  pore  (in  some 
of  the  dark  colored  varieties  there  are  several),  which  resembles  an 
ordinary  stoma  (Fig.  93).  Beneath  the  pore  is  a  cavity,  commonly  filled 
with  water  (Fig.  95,  I),  which,  by  evaporation,  deposits  calcium  car- 
bonate upon  the  walls  of  the  lining  cells,  thereby  discoloring  them.  A 
fibro-vascular  bundle  is  continued  from  the  veins  of  the  leaf  through 

*  In  •' Vergleichende  Anatomie  der  Vegetationsorgane,"  etc.,  1877, 
on  page  54,  et  seq.  References  are  there  given  to  the  literature  of  tho 
subject,  which  is  both  recent  and  limited.  After  Mettenius'  paper  in 
Filices  Jiorti  Lipsiensis,  others  appeared  by  other  writers  in  Botanische 
Zeitung,  1869,  1870,  and  1871, 


THE  EPIDERMAL  SYSTEM. 


105 


the  tooth  to  the  water-cavity  ;  iu  the  tooth  it  becomes  greatly  enlarged, 
and  is  there  composed  of  spiral  cells  (trache'ides),  which  surround  a 
central  mass  of  narrow  elongated  parenchymatous  cells  (Fig.  95,  c,  g). 
The  bundle  terminates  by  the  free  ends  of  the  parenchyma-cells  extend- 


Fi<?.  95.— Vertical  section  of  a  leaf-tooth  of  Fuchsia  globosa.  a.  vertical  longitudi- 
nal section  of  water-pore  ;  6,  water-cavity ;  c,  tracheldes ;  d,  chlorophyll-bearing 
parenchyma  :  e,  large  cell  containing  raphides  ;  /,  hair  ;  g.  parenchyma  of  the  flhro- 
vascnlar  bundle.  The  lower  part  of  the  figure  passes  into  the  leaf-blade,  x  125  — 
After  Arthur. 

ing  loosely  into  the  water-cavity.  Between  the  bundle  and  the  epider- 
mis of  the  leaf-tooth  lie  two  or  three  cell  layers  of  ordinary  chlorophyll- 
bearing  parenchyma,  in  which  there  are  occasionally  large  cells  con- 
taining raphides  (Fig.  94,  cp  and  ra)* 

*  The  foregoing  account  of  the  water-pores  of  Fuclwia  globosa,  and 
the  drawings  for  Figs.  93-4-5,  sire  taken  from  an  unpublished  papwr 
on  "  The  Water-Pores  of  Fuchsia  globow,"  by  J.  C.  Arthur. 


106  BOTANY. 

Water-pores  nearly  like  those  of  the  fuchsia  occur  ou  some  species  of 
Saxifraga,  Heudwra,  Mitetta,  Aconitum,  Delphinium,  Sambucus,  and 
many  other  plants. 

Another  form,  more  closely  resembling  the  ordinary  stomata  (but  of 
much  larger  size),  occurs  on  Tropaolum  Lobbianum,  Rochea  coccinea, 
and  others. 

§  III.    THE  FIBRO-VASCULAR  SYSTEM. 

133 — In  most  of  the  higher  plants  portions  of  the  pri- 
mary meristem  early  become  greatly  differentiated  into 
firm  elongated  bundles,  Avhich  traverse  the  other  tissues. 
They  are  composed  for  the  most  part  of  tracheary,  sieve, 
and  fibrous  tissues,  together  with  a  varying  amount  of  pa- 
renchyma. These  elementary  tissues  have,  with  some  con- 
siderable variations  in  the  different  groups  of  plants,  a  gen- 
eral similarity  of  arrangement  and  aggregation  throughout 
the  Pteridophytes  and  Phanerogams.  In  a  comparatively 
small  number  of  cases  laticiferous  tissue  is  associated  with 
the  above-mentioned  tissues.  To  these  aggregations  of  tis- 
sues the  name  of  Fibro-vascular  Bundles  has  been  given.* 

134. — In  many  plants  the  fibro-vascular  bundles  admit  of 
easy  separation  from  the  surrounding  tissues ;  thus  in  the 
Plantain  (Plantago  major]  they  may  readily  be  pulled  out 
upon  breaking  the  petioles.  In  the  leaves  of  plants,  where 
they  constitute  the  framework,  they  are,  by  maceration, 
readily  separated  from  the  other  tissues  as  a  delicate  net- 
work. In  the  steins  of  Indian  corn  the  bundles  run  through 
the  internodes  as  separate  threads  of  a  considerable  thick - 


135. — It  is  impossible  to  fix  upon  a  particular  form  as  the 
type  of  the  fibro-vascular  bundle.  It  should  be  understood 
at  the  outset  that  the  similarity  between  the  bundles  of 
widely  separated  groups  of  plants  is  only  a  general  one,  and 
that  there  are  great  differences  in  the  details  of  their  struc- 
ture. It  must  further  be  borne  in  mind  that  these  bundles 
are  not  themselves  tissues,  but  aggregations  of  dissimilar  tis- 


*  They  are  also  called  Vascular  Bundles  ;  this  term  ought,  however, 
to  be  retained  for  those  reduced  bundles  in  which  only  vessels  are  pres- 
ent— e.g.,  in  the  veinlets  of  leaves, 


THE  FIBRO-VA8CULAR  SYSTEM. 


sues,  any  of  which  may  be  wanting  in,  or  separated  a  little 
space  from,  the  bundle.  In  short,  the  elementary  tissues, 
particularly  tracheary,  sieve,  fibrous,  and  parenchymatous 
tissues,  are  to  be  considered  as  the  units,  and  the  term  Fibro- 
vascular  Bundle  as  little  more  than  a  convenient  expression 
of  the  usual  condition  of  aggregation  of  these  units.* 

The  general  structure  of  fibro-vascular  bundles  will   be 
more  readily  un- 
derstood   after 
the   examination 
of  a  number  of 
examples.  Those 
which  follow  are 
not  in  any  sense    "C^ 
typical  ;  they  are 
only  illustrative. 

136.— The  fi- 
bro-vascular bun- 
dle of  the  stem  of 
Pteris  aquilina 
is  composed  of 
tracheary  and 
sieve  tissues,  par- 
enchyma, and  a 
small  amount  of 
poorly  developed 
fibrous  tissue.  In 
transverse  s  e  c  - 
tion  the  bundle 
has  usually  an 
elliptical  outline. 


Fig.  96.—  Part  of  a  transverse  section  of  the  fibro-vas- 
cular  bundle  of  the  stem  of  Pleris  nqmlina  ;  «,  spiral  ves- 
sel; y,  g,  scalariform  vessels  ;  fp,  sieve  tissue:  A,  fibrous 
tissue  (protophloem  of  Russow)  ;  sg,  bundle  isheath;  py 
' 


,  y 

etarch-beanng  parenchyma:   A',  K,  thickened  angles  of 
The    great    mass    scalariform  vessels.-After  Sachs. 

of  the  bundle  is  made  up  of  large  scalariform  vessels, 
which  occupy  its  interior  (g,  g,  g,  Fig.  96).  Enclosed  in 
the  scalariform  tissue  are  masses  of  parenchyma  and  a  few 

*  By  considering  the  Fibro-vascular  Bundle  to  be  one  of  the  struc- 
tural units  of  the  higher  plants  a  serious  mistake  hag  been  made, 
leading  to  profitless  discussions  and  speculations  as  to  its  typical  struc- 
ture, and  diverting  attention  from  the  study  of  its  actual  structure. 


108 


spiral  vessels,  the  latter  occurring  near  the  foci  of  the  el- 
liptical cross-section  of  the  bundle  (s,  Fig.  96).  Surround- 
ing, or  partly  surrounding,  the  tracheary  portion  of  the  bun- 
dle is  a  layer  of  sieve  tubes  (sp,  Fig.  96),  separated  from  the 
large  scalariform  vessels  by  a  layer  of  parenchyma.  Outside 
of  the  sieve  tissue  is  a  mass  of  fibrous  tissue  (b,  Fig.  00"). 
which  is  itself  bounded  externally  by  another  layer  of  paren- 
chyma. The  whole  bundle  is  surrounded  by  a  layer  of  paren- 


Fig.  97. — Transverse  section  of  the  flbro-vaccnlar  bundle  of  the  rhizome  of  Poly  po- 
dium vulgare  ;  rp,  up,  narrow  spiral  vessels  in  the  edge  of  the  mass  of  scalariform  veu- 
Bels;  #,  region  of  the  sieve  tissue  filled  with  parenchyma  and  poorly  developed  sieve 
tissue  ;  u,  bundle  sheath,  outside  of  which  is  parenchyma.  X  225.— After  Be  Bary. 

chyma  differing  from  the  other  parenchymatous  tissues  in 
not  containing  starch  in  its  cells  ;  to  this  the  name  of  Bun- 
dle Sheath  has  been  given. 

A  noticeable  feature  in  the  structure  of  this  fibre-vascular 
bundle  is  that  the  tissues  have  a  concentric  arrangement ; 
the  tracheary  tissue  is  encircled  by  a  layer  of  parenchyma  ; 

See,  in  this  connection,  an  article  on  "  Some  recent  views  an  to  the  com- 
position of  the  Fibro- vascular  Bundles  of  Plants,"  by  S.  H.  Vines,  in 
Qr.  Jonr.  Mir.  Science,  1876,  p.  388. 


THK  FJBRO-VASCULAR  SYSTEM. 


109 


this  by  one  of  sieve  tissue  ;  this  again  by  fibrous  tissue,  and 
so  on. 

137. — A  similar  but  not  identical  structure  is  found  in  the 


Fig.  98.— Part  of  the  cross-section  of  an  old  root  of  Adiantum  Maritzlanum.  A,  k. 
ttainul  the  root  surface;  M,W,  bundle  sheath  (endodermis) ;  between  A  and  w.pa 
renchyma  ,  pc,  pericambium  ;  pr,  a  plate  of  tracheary  tissue,  which  is  bounded  ou 
each  side  by  sieve  tissue  X  225.— After  De  Bary. 

bundle  of  the  rhizome  of  Polypodium  vulgare.  Here  the 
f-entral  portion  of  the  stem  is  made  up  of  scalariform  tissue 
(Fig.  97,  the  larger,  thicker-walled  tissue),  and  this  is  sur- 
rounded by  a  tissue  which  may  be  regarded  as  but  partly 


110 


BOTANY. 


differentiated,  being  composed  of  parenchyma  and  poorlv 
developed  sieve  tubes  (s,  Fig.  97).  The  whole  bundle  is  sur- 
rounded, as  in  Pteris  aquilina,  by  a  bundle  sheath  (u,  Fig. 
97).  In  the  outer  part  of  the  mass  of  scalariform  tissue  are 
a  few  narrow  spiral  vessels  (sp,  sp,  Fig.  97),  but  they  are 
not  sufficiently  numerous  to  constitute  a  ring  or  layer. 
138. — In  the  root  of  Adiantum  Moritzianum  the  bundle 

consists  of  a  cen- 
tral plate  of  tra- 
cheary  tissue  ( pr, 
Fig.  98),  with  a 
mass  of  sieve 
tissue  on  each 
side  of  but  not 
quite  enveloping 
it.  Next  outside 
of  this  is  a  layer 
of  active  paren- 
chyma, the  peri- 
cambium  (pc, 
Fig.  98),  and  sur- 
rounding  the 
whole  is  a  poorly 
developed  bundle 
sheath  («.,  Fig. 
98). 

139.  — In   the 
stem  of  Equisc- 

Fig.  99.— Transverse  section  <  f  a  fibre-vascular  bundle  of  ,                 7 

Kqulsffjm  paluslrf.    r,  t,  ringed  vessel*  on  the  border  of  a  tuill   palUStre     it 

large  intercellular  canal  ;  «,  sieve  tissue  ;  ff,  q.  groups  of  • 

annular  and  reticiihted  vessels;    M.  the  so-called  general  1*   DOI  BO   easy  as 

bundle  sheath,  which  surrounds  all  the  bundks  ;  t,  i,  axial  ;,,    J-),P   fnrpo-ninr- 

air  canals;    x ,  x ,  fragments  of  the  ruptured  cells,     x  145.  m   tlie   lOregOing 

-After  De  Bary.  cages  to  mark  t  lie 

limits  of  the  bundles,  which  are  arranged  in  a  circle  about 
the  axis.*  On  the  axial  side  of  each  bundle  there  are  at 
first  a  few  spiral  and  annular  vessels,  most  of  which, 
along  with  a  considerable  amount  of  parenchyma,  are 

*  In  Equisetum  limosum,  however,  there  is  a  bundle  sheath  about, 
each  bundle,  consequently  there  is  in  that  species  no  difficulty  as  to 
the  limits  of  the  bundle. 


THE  FIBRO-VASCULAR  SYSTEM. 


in 


destroyed  shortly  after  their  formation,  thus  forming  a 
wide  canal  (Fig.  99;  t,  spiral,  and  r,  annular  vessels 
on  the  border  of  the  canal).  Immediately  in  front  of  01 
outside  of  the  canal  is  a  considerable  mass  of  sieve  tissue, 
made  up  of  true  sieve  tubes  and  the  nearly  allied  cambiform 
or  latticed  cells 
(«,  Fig.  99). 
Ilight  and  left  of 
the  sieve  tissue 
lie  a  few  annular 
and  reticulated 
vessels  (g,  g,  Fig. 
99).  Exterior  to 
all  the  bundles 
(in  this  species) 
is  a  cellular  lay- 
er, which  has  re- 
ceived the  name 
of  bundle  sheath, 
but  which,  prob- 
ably, has  no  rela- 
tion to  the  lay- 
er so  named  that 
surrounds  each 
fibro  -  vascular 
bundle  of  some 
plants. 

140.  — The 

Structure   of    the  Fig.  100.— Cross-section  of  the  stem  of  SelatftneUa  inaequl- 

,          -n     •       07       •  folia,  showing  three  bundles;  in  each  bundle  the  inner 

bundle  in  belagi-  thicker  walk-d  tissue  is  composed  of  realarift  .rm  vessels; 

•              'ft*!'  with  a  few  narrow  spiral  vessels  on  each  extreme  margin  : 

inceqUlfOlia  surrounding  the  ecalarform  tissue  is  the   tHunor  walled 

f)   nnrxsirW  sieve  tissue,  and  around  this  ajrain  is  a  layer  of  cell-,  which 

a  Consider-  may  be  c.xlled  the  bundle  ^u-ath  ;  I,  I,  intercellular  spaces 

able  resemblance  surroundlllg  *he  bundles,  x  iso.— After  Sachs, 
to  that  of  Pteris  aquilina.  There  is  in  each  bundle  a 
central  plate  of  tracheary  tissue,  consisting  of  a  few  narrow 
spiral  vessels  in  its  two  edges  and  a  remaining  mass  of  scala- 
riform  vessels  (Fig.  100).  The  tracheary  portion  is  sur- 
rounded by  a  tissue  of  elongated,  thin-walled  tissue  which 
is,  at  least  in  part,  a  sieve  tissue.  In  this  and  allied  species 


112  HOT  ANY. 

the  bundles  are   curiously   isolated   from   the   surrounding 
ground  tissues  of  the  stem. 

141. — The  bundle  of  the  nearly  related  Lycopodium  cnm- 
planatum  is  much  more  complex  in  its  structure  (Fig.  101). 
Here  there  are  four  parallel  plates  of  tracheary  tissue,  each 
having  a  structure  like  the  single  plate  of  the  bundle  of 
Selaginella  in&quifolia.  Between  the  tracheary  plates  there 
is  in  each  case  a  row  of  sieve  tubes  imbedded  in  a  lignified 
tissue  composed  of  elongated  cells  (sclerenchyma,  or  fibrous 


Pig.  101.— Crops-section  of  the  stem  of  LycopOfHitm  rnrnftannturn.  The  fibro-vas- 
cnlar  bundle  is  composed  of  four  plates  of  irach<  ary  ti.-sue  (darker  in  the  figure), 
between  which  are  masses  of  lignifled  tissue  composed  of  elongated  cells  ;  each  of 
these  laiter  masses  enclose?  a  row  of  sieve  tubes  (larger  and  thicker  walled  in  the 
figure) :  the  bundle  sheath  is  seen  to  bound  on  its  inner  side  a  thick  mass  of  very  thick 
walled  fibrous  tissue ;  exterior  to  this  (toward  B)  is  a  layer  of  chlorophyil-bearing 
parenchyma,  bounded  by  a  well-developed  epidermis.  The  small  vessels  at  the  ex- 
treme edges  of  the  plates  of  tracheary  tissue  are  narrow  and  .spirally  marked  ;  the 
remainder  of  each  plate  is  composed  of  scalariform  vessels,  x  100.— After  Sachs. 

tissue?).  Around  this  central  fibro-vascular  portion  there  is 
a  layer  of  parenchyma,  and  outside  of  this  a  bundle  sheath, 
which  is  commonly  regarded  as  marking  the  boundary  of 
the  bundle  ;  it  is  doubtful,  however,  whether  it  should  be  so 
considered,  as  exterior  to  it  lies  a  thick  mass  of  fibrous  tissue 
which  completely  envelops  all  the  previously  described 
tissues.* 


*  Sachs  ("Text-Book,"  p.  418)  rejrards  ;he  stem  of  Lycopodium  as 
composed  of  four  united  bundles  and  compares  them  to  the  separate 
bundles  of  Selaginella.  De  Bary  ("  Anatomie,"  etc.,  p.  362),  on  the 


THE  PIBKO  VASCULAR  SYSTEM. 


113 


142. — In  the  fibro-vascular  bundle  of  the  stem  of  Indian 
corn  (Zea  mais)  the  central  portion  is  composed  of  tracheary 


Fig.  102.— Transverse  section  of  fibro-vascular  bundle  of  Indian  corn  (Zea  mais). 
a,  side  of  bundle  looking  toward  the  circumference  of  thoftem;  i,  side  of  bundlelook- 
ing  toward  the  centre  of  the  stem  ;  p,  thin-walled  parenchyma  of  the  fundamental 
tissues  of  the  stem;  ff,  g,  large  pitted  vessels;  «,  spiral  vessel;  r,  rin^ot  an  annular 
vessel ;  I,  air-cavity  formed  oy  the  breaking  apart  of  the  surrounding  cells;  v,  v, 
latticed  cells,  or  soft  bast,  a  form  of  sieve  tissue.  X  550.— After  Sachs. 

tissue,  consisting"  of  pitted,  spiral,  ringed,  and  reticulated 
vessels  (Fig.  102,  #,  g,  8,  r,  and  the  tissue  between  v — s,g — g) 

other  hand,  considers  the  cylindrical  portion  in  the  centre  as  but  one 
bundle,  belonging  to  what  he  terms  the  Radial  type.  Both  agree  in  con- 
sidering the  fibrous  tissue  outside  of  the  bundle  sheath  as  not  belong- 
ing to  the  bundles  ;  but  certainly  if  this  is  one  bundle,  there  is  as  good 
reason  for  including  the  fibrous  cylinder  in  it  as  there  is  in  the  case  of 
thf  bundle  of  Indian  corn. 


114 


SOTANT. 


Lying  by  the  side  of  the  tracheary  tissue  (on  its  outer  aide  as 
it  is  placed  in  the  stem)  is  a  mass  of  sieve  tissue,  composed  of 
latticed  cells  (v,  v,  Fig.  102).  Surrounding  the  whole  is  a 
thick  mass  of  fibrous  tissue  composed  of  elongated,  thick- 
walled  cells  (the  shaded  ones  in  the  figure). 

143. — The  fibro-vascular  bundle  of  the  flowering-stalk  of 
Acorus  calamus  bears  a  close  resemblance  to  that  of  Indian 
corn.  Like  that,  it  has  a  central  tracheary  portion  (g,  Fig. 
103),  which  has  lying  exterior  to  it  a  mass  of  sieve  tissue  (w, 

Fig.  103).  On  the  inner 
side  there  is  a  large  in- 
1  ercellular  canal,  evi- 
dently holding  the  same 
relation  to  the  other 
tissues  that  the  smaller 
canal  does  in  the  bundle 
of  Indian  corn.  The 
exterior  of  the  bundle 
is  here  also  made  up  of 
a  thick  mass  of  fibrous 
tissue. 

144.  —  In  the  fibro- 
vascular  bundle  of  the 
adventitious  roots  of 
Acorus  calamus  the  ar- 
rangement of  the  tis- 

Flg.  103.— Transverse  section,  of  a  portion  of  -,•& 

the  general  peduncle  of  Acorus '  calamw.    «,  epi-    SUCS     IS     VCrv      different 
dennis  ;  b.  small  flbro-vascular  bundle  ;  in  the 
hirge  bundle  w  is  the  si«-v«  ti^ne,  Q  the  trache- 


ary tissue,  /an  intercvllular  canal ;  the  peril 
of  the  hmullc  is  composed  of  thick-walled  fibre 
tissue  (figured  oark).     x  145.— Alter  De  Bary. 


very 

from  that  described 
above.  Here  there  are 
many  rad  ially  placed 
plates  of  tracheary  tissue  (pp,  Fig.  104),  which  alternate 
with  thick  masses  of  sieve  tissue  (ph,  Fig.  104).  Between 
these  alternating  tissues,  and  within  the  circle  formed  by 
them,  there  is  a  mass  of  parenchymatous  tissue.  The 
whole  bundle  is  separated  from  the  large-celled  parenchyma 
of  the  root  by  a  well-marked  bundle  sheath  (s,  Fig.  104)  ; 
the  latter  is  bounded  interiorly  by  a  layer  of  active  thin- 
walled  cells  —  the  pericambium  —  from  which  new  roots 
originate.  In  the  older  root,  the  central  cell  mass  (which, 


THK  FIBRO- VASCULAR  SYSTEM.  115 

as  described  above,  is  in  younger  specimens  composed 
of  parenchyma)  is  transformed  into  sclerenchyma  (Fig. 

105). 

145 The  fibro-vascular  bundles  of  Ricinus  communis 

have  an  arrangement  in  the  stem,  and  a  general  structure 
somewhat  similar  to  those  of  Equisetum  palustre,  described 
above.  The  limits  of  the  bundles  are  so  poorly  marked  that 


Fig.  104.— Transverse  section  of  the  fibre-vascular  bundle  of  the  root  of  Aconif 
calamus.  «.  bundle-sheath  (also  called  endodermis),  with  parenchyma  outside  and  a 
single  layer  of  pericambium-cells  inside :  pp.  plates  of  radially-plac  d  tracheary 
tissue  ;  ;>/t,  bundles  of  sieve  tissue ;  pp.  narrow  peripheral  (and  first  formed)  ves- 
sels ;  g,  large  and  still  young  vessel.— After  Sachs. 

in  places  it  is  impossible  to  tell  whether  the  tissues  belong 
to  them  or  to  the  surrounding  ground  tissues. 

The  inner  portion  of  the  bundle  (g,  g,  t,  t.  Fig.  106,  and  s 
to  #,  Fig.  107)  is  made  up  of  tracheary  tissue  of  several  varieties; 
on  the  inner  edge  of  this  tracheary  portion  lie  several  spiral  ves- 
sels (s,  s,  Fig.  107)  ;  next  to  these,  on  their  outer  side,  are  sca- 
lariform  and  pitted  vessels  (/,  f,  g,  g,  Fig.  106,  I,  t,  t',  Fig. 
107),  intermingled  with  elongated  cells,  whose  walls  arc  pitted 


116  BOTANY. 

(h,  h' ,  h",  h'",  Fig.  107).  The  last-named  are  clearly  related 
to  the  vessels  which  surround  them,  and  from  which  they 
differ  only  in  their  less  diameter,  and  in  having  imperforate 
horizontal  or  oblique  septa.  They  are  doubtless  properly 
classed  with  the  Tracheides  (see  p.  84).  On  the  outer  side  of 
the  tracheary  portion  just  described  lies  a  mass  of  narrow, 
somewhat  elongated,  thin-walled  cells,  which  constitute  a 
true  meristem  tissue,  to  which  the  name  of  Cambium*  has 
been  given  (c,  c,  Figs.  100  and  107).  Next  to  the  cambium 


Pig.  105.— A  very  thin  cross-section  of  the  radial  fibre- vaecular  bundle  of  an  old 
adventitious  root  of  Acorns  calamus,  g,  the  radial  plates  of  tracheary  tissue  ;  w,  the 
sieve  tissue  alternating  with  the  plates  of  tracheary  tit-sue  ;  «,  the  bundle-sheath ; 
the  tissue  in  the  centre  of  the  bundle  is  sclerenchyma.  x  145.— After  De  Bary. 

lie,  in  order,  sieve  tissue  and  parenchyma;  these  do  not  occupy 
separate  zones,  but  are  more  or  less  intermingled,  forming 
a  mass  sometimes  called  the  Soft  Bast  (y,  y,  y,  Fig.  106,  and 
p,  Fig.  107).  The  sieve  tissue  includes  sieve  tubes  and 
cambiform  or  latticed  cells.  In  the  extreme  outer  border  of 
the  bundle  is  a  mass  of  fibrous  tissue  (b,  b,  Figs.  106  and  107). 
The  layer  of  starch-bearing  cells  just  outside  of  the  last- 
named  tissue  is  the  so-called  bundle  sheath. 

*  Cambium,  a  low  Latin  word,  meaning  u  liquid  which  becomes 
orlutinous.  The  term  wns  introduced  wh.-n  the  real  structure  of  the 
part  to  which  it  was  applied  was  not  understood. 


THE  FIB RO-  VASCULAR  SYSTEM. 


117 


146. — The  bundle  of  the  adventitious  root  of  Ranunculus 
repens  is  very  different  from  the  one  just  described.  It  may 
be  briefly  described  as  composed  of  a  mass  of  tracheary  tis- 


Fig.  106.— Transverse  section  of  hypocotyledonary  portion  of  stem  of  Ricinus  com- 
mimis.  r,  r,  parenchyma  of  the  prinnry  cortex  ;  w,  parenchyma  of  the  pith  •.  b, 
bast  fibres  ;  y,  y,  soft,  bast;  c,  cambium  ;  g,  g,  large  pitted  vessels  ;  t,  t,  smaller  pit- 
ted vessels  ;  cb,  continuation  of  the  cambium  into  the  pan-nchjma  lying  between  the 
bundles— the  parenchyma-cells  are  repeatedly  divided  by  tangential  walls.  Between 
the  primary  cortex  r  and  the  fibrous  tissue  of  the  phloem  lies  a  layer,  the  so-called 
bundle-sheath,  filled  with  compound  starch  grains.  Highly  magnified. — After  Sachs. 

sue,  which  is  cross-shaped,  as  seen  in  transverse  section  (g, 
r,  g,  Fig.  108),  and  four  masses  of  sieve  tissue,  which  lie  in 
the  angles  between  the  projecting  portions  of  the  traoheary 
tissue.  Around  the  whole  is  a  layer  of  pericambium  (p, 


118 


BOTANY. 


Fig.  108),  and  exterior  to  this  is  the  bundle  sheath  (u,  Fig. 
108). 

147. — In  Gymnosperms  and  Dicotyledons  the  fibro-vascu- 
lar  bundles  of  the  stems  have  a  structure  essentially  like  that 
of  Ricinus  communis,  described  above  In  them  it  is  evi- 
dent at  a  glance  that  the  bundle  is  divided  into  two  some- 
what similar  portions,  an  inner  and  an  outer,  by  the  cam- 


h    I, 


Pig.  107.-Longitndinal  radial  section  of  the  fit 


-  - 

it  (the  transverse  section  being  shown  in  Fig. 
cortox  ;  0«,  bundle  sheath  ;  in,  parenchyma  o 


bium  zone.  Xiigeli,*  who  first  pointed  out  these  divisions, 
named  the  inner  one  the  Xylem  portion,  because  from  it  the 
Avood  of  the  stem  is  formed  ;  the  outer  he  named  the  Phloem 
portion,  for  the  reason  that  it  develops  into  bark.f  In 
pome  cases  the  similarity  between  the  structure  of  xylem 


*  "  Beitrage  zur  Wissenschaftlichnn  Botanik,"  1858. 
f  Xylem  from  £i;/oi<,  wood  ;  Phloem  from  Greek  ^ot 


bark. 


THE  F1BRO-VA8VULAR  SYSTEM. 


119 


and  phloem  is  so  marked  that  they  are  said  to  be  composed 
of  corresponding  tissues.  (1)  Vascular,  (2)  Fibrous,  and  (3) 
Parenchymatous. *  The  vascular  tissues  are,  on  the  one 
hand,  the  tracheary  tissue  found  only  in  the  xylem,  and  on 
the  other,  the  sieve  tissue  of  the  phloem.  The  fibrous  tissue 
of  the  xylem  is  the  variety  with  the  shorter  and  harder 


Fig.  108.— Cross- 8ection  of  the  flbro-vascular  bundle  of  an  old  adventitious  root  of 
nwm nodus  repent.  </,  a,  ff,  the  outer  margins  of  the  radial  plates  of  tracheary  tisane  ; 
?-,  a  large  central  pitted  vessel ;  x,  septum  in  pitted  vessel,  with  its  central  portion 
HOsorbed  ;  p,  pericambinm  ;  u,  bundle  sheath  ;  between  the  four  projecting  parts  of 
the  tracheary  portion  of  the  bundle,  and  just  within  the  pericambium,  lies  the  sieve 
tissue,  x  145. -After  De  Bary. 

fibres,  known  as  wood  fibres ;  that  of  the  phloem  is  com- 
posed of  the  longer  and  tougher  bast  fibres.  The  paren- 
chyma of  the  two  portions  is  much  alike. 

*  Attention  should  be  called  here  to  tlie  fact  that  in  a  good  many 
orders  of  Phanerogams  the  laticiferous  vessels  are  constituent  parts  of 
the  flbro-vascular  bundles.  Thus  in  Cichoriaceae,  Campanulaceae, 
Papaveracese,  Asclepiadaceae,  Apocynacese,  and  Acerineae  they  occur  in 
the  phloem;  in  Papayacese  and  Aroideae  they  occur  in  the  xylem. 


120  130TANY. 

148. — Nageli  extended  this  classification  of  the  tissues  to 
the  fibro-vascular  bundles  of  Monocotyledons,  and  subse- 
quently it  has  been  still  further  extended  so  as  to  include  all 
kinds  of  fibro- vascular  bundles.  In  every  case  the  tracheary 
portion  is  the  essential,  or  most  constant,  characteristic  of 
the  xylem,  as  the  sieve  tissue  is  of  the  phloem. 

These  terms  are  valuable  when  used  in  reference  to  the 
fibro- vascular  bundles  of  the  stems  of  Phanerogams ;  they 
may  also  be  valuable,  if  properly  used  and  understood,  when 
applied  to  other  forms  of  the  fibre-vascular  bundle.  The 
xylem  portions  of  the  stem  bundles  of  different  plants 
among  the  Phanerogams  are  homologous  parts  of  the  tissue 
systems — the  bundles  ;  but  when  the  term  xylem  is  applied 
to  certain  parts  of  two  dissimilar  bundles — e.g.,  of  Ricinus 
(Fig.  106)  and  Lycopodium  (Fig.  101) — no  homology  of  parts 
should  be  understood.  The  tissues  themselves,  in  some 
cases  of  dissimilar  bundles,  may  be  homologous,  but  they  are 
homologous  tissues,  and  not  homologous  parts  of  a  system 
of  tissues.*  When,  therefore,  these  terms  are  used  in  the 
present  work,  it  must  be  borne  in  mind  that  they  do  not 
necessarily  convey  the  idea  of  homology  of  parts. 

149. — De  Bary's  f  recent  structural  classification  of  fibro- 
vascular  bundles  is  useful  in  designating  their  general  plan. 
He  includes  all  forms  under  three  kinds,  viz.,  (1)  the  Col- 
lateral bundle,  which  has  one  mass  of  xylem  by  the  side  of 
a  single  mass  of  phloem  ;  this  is  the  form  of  all  bundles  of 
the  stems  of  Equisetum,  and  of  the  stems  and  leaves  of  Pha- 
nerogams I  (Figs.  99,  102, 103, 106, 107) ;  (2)  the  Concentric 


*  This  point,  which  is  an  important  one,  may  be  made  clearer  by  an 
illustration  from  zoolojry.  The  nervous  tissue  of  one  animal  is  the 
homologue  of  that  found  in  any  other,  but  the  nervous  system  of  one 
may  or  may  not  be  the  homologue  of  the  other.  The  nervous  system 
of  the  bee,  for  example,  is  not  the  homologue,  but  the  analogue,  of 
that  of  the  ox  ;  it  is,  however,  the  homolojfue  of  the  nervous  system 
of  the  lobster.  The  brain  of  the  ox  and  the  brain  of  the  bee  are  not 
homologues  as  parts  of  a  system,  but  they  are  homologues  as  tissues. 

f  "  Vergleichende  Anatomie,"  etc.,  p.  331,  et  seq. 

\  In  the  Cucurbitacwe  and  some  other  orders  there  is  a  mass  of  sieve 
tissue  on  the  inner  side  of  the  xylem,  so  that  the  latter  is  between  two 


THE  FIBRO-VASCULAR  SYSTEM.  121 

bundle,  which  has  its  tissues  arranged  concentrically  around 
one  another ;  this  is  the  bundle  of  the  stems  and  leaves  of 
ferns  (with  a  few  exceptions),  Selaginellae,  and  a  few  excep- 
tional cases  in  Phanerogams  (Figs.  96,  97,  98,  100) ;  (3)  the 
Radial  bundle,  which  has  its  tissues  arranged  radially  about 
its  axis  ;  such  a  bundle  occurs  in  the  stems  of  Lycopodium, 
and  it  is  the  primary  bundle  of  the  roots  of  most  Pterido- 
phytes  and  Phanerogams  (Figs.  101,  104,  105,  108). 

150. — The  development  of  the  fibro- vascular  bundle  takes 
place  in  this  wise:  in  the  previously  uniform  Primary  Meris- 
tem  there  arises  an  elongated  mass  of  cells,  constituting  the 
Procambium  of  the  bundle ;  as  it  gnws  older  the  cells, 
which  were  at  first  alike,  become  changed  into  the  vessels, 
fibres,  and  other  elements  of  the  bundle  tissues.  In  the 
fibro-vascular  bundle  of  the  stems  and  leaves  of  Gymno- 
sperms  and  Dicotyledons  this  change  begins  on  the  two  sides 
of  the  bundle — i.e.,  on  the  outer  edge  of  the  phloem  and 
the  inner  edge  of  the  xylem  ;  from  these  points  the  change 
into  permanent  tissue  advances  from  both  sides  toward  the 
centre  of  the  bundle.  In  some  cases  (e.g.,  in  the  leaves) 
all  of  the  procambium  is  changed  into  permanent  tissue, 
forming  what  is  termed  the  closed  bundle;  in  other  cases 
there  is  left  between  the  phloem  and  xylem  a  narrow  zone 
of  the  procambium  (now  called  the  Cambium),  forming 
what  is  known  as  the  open  bundle. 

151. — In  the  stem  and  leaf  bundles  of  Monocotyledons 
the  development  of  procambium  into  permanent  tissue  is 
essentially  as  in  Dicotyledons  and  Gymnosperms,  with  this 
difference,  that  here  they  all  become  closed.  In  Pteridophytes 
and  the  roots  of  Phanerogams  the  development,  while  agree- 
ing in  general  with  the  foregoing,  is  quite  different  as  to  de- 
tails ;  all  are  closed,  unless  those  in  the  roots  of  Dicotyledons 
and  Gymnosperms  should  be  shown  to  be  exceptions. 

152. — The  fibro-vascular  bundles  of  leaves  and  the  re- 
productive organs  are  quite  generally  reduced  by  the  absence 

so-called  phloem  portions.  Such  bundles  are  considered  by  De  B.iry  to 
be  variations  of  the  collateral  form,  aud  he  designates  them  as  bi-col- 
lateral  bundles. 


122 


BOTANY. 


of  one  or  more  tissues;  this  reduction  may  be  so  great  as  to 
leave  but  a  single  tissue,  which  in  many  cases  is  composed  of 
only  a  few  spiral  vessels  or  trachoiides  (Fig.  109).  In  other 
cases,  instead  of  spiral  vessels  the  bundle  may  consist  of  a  few 
fibres  of  bast ;  or  of  elongated,  thin-walled  cells,  which  are 
doubtless  to  be  regarded  as  meristem-cells  which  failed  to 
fully  change  into  one  of  the  or- 
dinary permanent  tissues  ;  this 
last  is  a  very  common  accom- 
paniment of  reduced  bundles. 

(a)  In  the  study  of  the  structure 
of  fibro-vascular  bundles  mucli  care 
is  required  in  the  preparation  of  the 
specimens.  The  thin  transverse  sec- 
tions are  obtained  by  ordinary  pro- 
cesses with  no  great  difficulty,  but 
such  is  not  the  case  with  the  lon- 
gitudinal sections  ;  they  must  not 
only  be  extremely  thin,  but  must  run 
parallel  with  the  cells  and  fibres, 
and  moreover,  must  be  sufficiently 
large  to  show  all,  or  a  considerable 
part,  of  the  bundle.  It  is  necessary 
also  to  have  several  longitudinal 
sections,  and  to  know  the  exact  posi- 
tion of  each  one  when  compared 
with  the  transverse  section. 

(ft)   The  most  satisfactory   results 
can  be  obtained  only  by  the  use  of 
Fig.  109.-Terminal  ramifications  of    some  mechanical  section-cutter.*    In 
the  reduced  fibro-vascular  bundles  of    most   cases   the    sections   are    made 
the  leaf  of  Pnoraltu  f>i/nminosa;  the  .,        .  ,  .          , 

ends  x,  x,  are  cut  ..ff  in  making  the    more  easily  after  soaking  the  stems, 
roots  or  leaves  used  in  alcohol. 


preparation,  the  other*  are  the  actn 
termini  ;  the  bundles  are  seen  to  be 
composed  of    spiral    tracheldes.   and 

ESS  e 


(c)  In  many  cases  it  is  profitable 
to  macerate   some  of  tlie  longitudi- 
nal sections  in  nitric  acid  and  potassi- 
um chlorate  (Schulze's  maceration), 
so  as  to  permit  of  an  isolation  of  the  fibres,  cells,  and  vessels. 

(d)  Good    specimens  for   study  may   be   obtained   from  any  of  the 
higher  plants,  but  the  examination  will  be  most  profitable  if  the1  order 


cells  of  the  chlorophyll-bearing  part-n 
chyma.    X  22o.-After  De  Bary. 


*  For  the  various  contrivances  used  for  cutting  sections  see  the  com- 
mon books  on  microscopy,  also  American  Naturalist,  1874,  p.  59 ; 
American  Quarterly  Microscopical  Join  mil,  1879,  p.  131,  and  several 
articles  in  Qr.  Jour.  Mic.  Science,  1870, 1874, 1875,  1877. 


THE  FUNDAMENTAL  SYSTEM.  123 

in  the  following  list  of  examples  is  observed  :  (1)  the  rhizomes  and 
roots  of  ferns  ;  (2)  stems  of  Selaginella  and  Lycopodium  ;  (3)  stems  of 
Monocotyledons  ;  (4)  stems  of  Equisetum  ;  (5)  young  stems  of  Gymno- 
sperms  and  Dicotyledons ;  (6)  roots  of  Phanerogams ;  (7)  reduced 
bundles  of  leaves. 

(c)  The  discussion  of  the  disposition  of  the  bundles  in  the  stem,  and 
their  relation  to  the  leaf  bundles,  together  with  the  development  and 
structure  of  secondary  bundles,  belongs  properly  to  the  special  anatomy 
of  the  Phanerogams.  (See  Chapter  XX.) 

§  IV.   THE  FUNDAMENTAL   SYSTEM,  OR  THE   SYSTEM  OF 
GROUND  TISSUES. 

153.— These  terms  refer  to  the  mass  of  various  tissues 
lying  within  the  epidermis,  and  not  included  in  the  fibro- 
vascular  bundles,  when  they  are  present.  In  passing  down 
through  the  lower  plants  this  inner  mass  becomes  more  and 
more  simple,  until  it  is  composed  of  but  one  homogeneous 
tissue,  when  the  term  system  can  no  longer  be  profitably 
applied  to  it ;  in  passing  to  the  higher  plants,  on  the  other 
hand,  there  is  in  this  portion  of  their  structure  an  increasing 
complexity,  which  comes  at  last  to  more  than  equal  that  of 
either  the  epidermal  or  fibro- vascular  systems. 

154.— In  its  fullest  development,  the  fundamental  system 
may  contain  parenchyma  of  various  forms,  collenchyma, 
sclerenchyma,  laticiferous  tissue,  and  possibly  also  fibrous 
tissue.*  Their  arrangement,  within  certain  limits,  presents 
a  considerable  degree  of  similarity  in  nearly  related  groups 
of  plants,  but  this  is  by  no  means  as  marked  as  in  the  case  of 
the  fibro-vascular  system. 

*  It  is  a  question  whether  fibrous  tissue  occurs  in  the  fundamental 
system  ;  there  are  some  cases  (e.g.,  in  Ferns,  Lycopodiaceae,  etc.) 
which  appear  to  show  that  it  does,  but  possibly  they  admit  of  other  in- 
terpretation. It  should  be  mentioned  here  that  many  eminent  botanists 
(notably  Schwendener,  Russow,  Falconberg,  and  De  Bary)  hold  that  all 
fibrous  tissue  belongs  to  the  fundamental  system,  and  as  a  consequence, 
that  it  in  no  case  is  a  proper  constituent  of  the  fibro-vascular  bundle. 
This  is,  however,  nothing  more  than  making  a  typical  form  of  bundle 
(composed  of  tracheary  and  sieve  tissues),  and  then  insisting  that  all  tis- 
sues not  found  in  the  type  are  extra-fascicular,  a  course  which  cannot 
be  followed  in  this  book. 


124 


BOTANY. 


(1.)  Parenchyma  is  the  most  constant  of  the  fundamental 
tissues  ;  it  makes  up  the  whole  of  the  interior  plant-body  in 
those  cases  where  there  has  been  no  differentiation  into  more 
than  one  tissue,  and  from  here,  it  is  present  in  varying 
amount  in  nearly  all  (if  not  all)  cases  up  to  and  including 
the  highest  plants.  In  stems  of  Monocotyledons  it  makes  up 
the  mass  of  tissue  lying  between  the  scattered  bundles,  and 
in  stems  of  Gymnosperms  and  Dicotyledons  it  constitutes 
the  pith  and  portions  of  the  bark. 

(2.)  Collenchyma,  when  present,  as  it  frequently  is  in  the 
stems  and  leaves  of  Dicotyle- 
dons, is  always  either  in  con- 
tact with  or  near  to  the  epi- 
dermis. 

(3.)  Sclerenchyma  is  com- 
mon beneath  the  epidermis 
of  the  stems  and  leaves  of  Bry- 
ophytes,  Pteridophytes,  and 
Phanerogams.  It  appears  to 
replace  collenchyma  in  parts 
having  greater  firmness  than 
that  given  by  the  latter.  Some 
forms  of  sclerenchyma  are 
scarcely  to  be  distinguished 
from  fibrous  tissue — e.g.,  in 
the  hypoderma  of  pine  leaves 
(Fig.  110,  y,  i').  It  may  be 
that  the  supposed  cases  of  fibrous  tissue  among  the  funda- 
mental tissues  will  turn  out  to  be  sclerenchyma  instead. 

(4.)  Laticiferous  tissue  may  occur,  apparently,  in  any  por- 
tion of  the  fundamental  system  of  Phanerogamous  plants. 

155.— It  is  thus  seen  that  in  general  the  tissues  of  the 
fundamental  system  are  so  disposed  that  the  periphery  is 
harder  and  firmer  than  the  usually  soft  interior,  although 
there  are  many  exceptions.  This  general  structure  has  given 
rise  to  the  term  Hypoderma  for  those  portions  of  the  funda- 
mental system  which  lie  immediately  beneath,  or  near  to  the 
epidermis.  Hypoderma  is  not  a  distinctly  limited  portion — 
in  fact,  it  is  often  difficult  to  say  how  far  it  does  extend ; 


Fig.  110.— Margin  of  leaf  of  Pimti  pin- 
aster, tranevorse  section  ;  c,  cnticular- 
ized  layer  of  outer  wall  of  epidermis  ;  i, 
inner  non-cuticularized  layer ;  c',  thick- 
ened outer  wall  of  marginal  cell  ;  g,  i', 
hypoderma  of  elongated  sclereiichyma  ; 
p,  chlorophyll-bearing  parenchyma  ;  pr, 
contracted  protoplasmic  contents.  X 
800.— After  Sachs. 


THE  FUNDAMENTAL  SYSTEM. 


125 


however,  it  usually  includes  several,  or  even  many,  layers  of 
cells,  or  the  whole  of  each  of  the  tissue-masses  (e.g.,  colleu- 
chyma,  sclerenchynia,  etc.)  which  immediately  underlie  the 
epidermis  (Fig.  110,  g,  i). 

The  remaining  portion  of  the  fundamental  system,  inside 
of  the  hypoderma,  is  designated  by  Sachs  as  the  Intermediate 
tissue.  The  term  is  of  but  little  value  in  many  of  the  higher 
plants,  where  more  particular  names  may  be  applied  ;  but  in 
some  Monocotyledons,  most  Pteridophytes,  and  in  Bryo- 
phytes  it  is  very 
serviceable. 

156.  — Cork. 
Within  the  zone 
which  the  hypo- 
•  derma  includes 
there  frequently 
takes  place  a  pe- 
culiar develop- 
ment of  the 
young  parenchy- 
ma, giving  rise 
to  layers  of  dead 
cells,  whose  cav- 
ities are  filled 
with  air  only. 
The  walls  in 
some  cases  (e.g., 

tlio  r>r»T-lr  r»oV\  aro 
tne  COrK-OaKj  aie 

thin    and    weak, 

while  in  others  (e.g.,  the  beech)  they  are  much  thickened, 
and  in  all  cases  they  are  nearly  impermeable  to  water.  True 
cork  is  destitute  of  intercellular  spaces,  its  cells  being  of 
regular  shape  (generally  cuboidal)  and  fitted  closely  to  each 
other  (Fig.  111). 

157. — Cork  substance  is  formed  by  the  repeated  subdivis- 
ion of  the  cells  of  a  meristem  layer  of  the  fundamental  tissue 
(Fig.  Ill)  ;  these  continue  to  grow  and  divide  by  parti- 
tions parallel  to  the  epidermis,  forming  layers  of  cork  with 
its  cells  disposed  in  radial  rows  (Fig.  Ill,  k).  Shortly  after 


Fig.  111. — Transverse  section  of  one-year  old  stem  of  Ai- 
lant/itig  glandulosm.  e.  epidermis  ;  *,  cork-cells  ;  r,  inner 
green  cells,  the  phelloderma  ;  between  k  itnd  r  a  layer  of 
cells  tilled  with  protoplasm,  called  the  phellogen  or  cork 
cambium.  X  350.— After  Prantl. 


136  BOTANY. 

their  formation  the  cork-cells  lose  their  protoplasmic  con- 
tents, while  beneath  them  new  cells  "are  constantly  being  cut 
off  from  the  cells  of  the  generating  layer  ;  in  this  way  the 
mass  of  dead  cork  tissue  is  formed  and  pushed  out  from  its 
living  base. 

158.—  The  generating  tissue  is  called  the  Phellogen,*  or 
Cork-cambium  ;  it  occurs  not  only  in  the  hypoderma,  but  in 
any  other  part  of  the  fundamental  system,  and,  as  will  be 
shown  hereafter,  in  the  secondary  fibro-  vascular  bundles. 
AVhen  a  living  portion  of  a  plant  is  injured,  as  by  cutting, 
the  uninjured  parenchyma-cells  beneath  the  wound  often 
change  into  a  layer  of  phellogen,  from  which  a  protecting 

mass  of  cork  is  then 
developed. 

159.  —  Lenticels 
are  in  many  cases  the 
result  of  a  restricted 
corky  growth  just  be- 
neath a  stoma.  Phel- 
logen consisting  of  a 

few  Cells  Of  the  hypo- 

Fig.  112  —Transverse  section  of  a  portion  of  the  ,                ...              ,*T 

internode  of  a  younj.'  twig  of  R*tnla  nlt>a.    c,  cuticle,  derma,  IS  formed   im- 

somewhat  separated  from  the  epidermis  ;  <>,  e,  epider-  -,.    ,    ,          ,     , 

mis  ;  a,  cavity  under  ihe  htomaeeen  in  cros^ection  mediately       DCIOW       a 

abov<;  ;  a,  x,  cells  whi<  h  are  beginning  the  process  of  04-r.rrlo    /T?\rr     11O    ™\  . 

multiplication  by  fission.  conMftutins  ;  the  phellogen  Stoma    (big.    112,  X)  J 

of  the  future  lenticel.     X  875.  -After  De  Bary.  by  the  growth  of  COrk 

from  this  phellogen  the  epidermis  is  pushed  out  and  finally 
ruptured,  exposing  the  roundish  or  elongated  mass  of  corkf 
(Fig.  113).  Lenticels  are  of  frequent  occurrence  on  the  young 
branches  of  birch,  beech,  cherry,  elder,  lilac,  etc.,  and  may  be 
distinguished  by  the  naked  eye  as  slightly  elevated  roughish 
spots,  usually  of  a  different  color  from  the  epidermis. 

(«)  The  examination  of  the  tissues  of  the  fundamental  system  may 
in  general  be  made  with  considerable  ease,  by  making  trans  verse,  tan- 
gential and  radial  sections. 


*  From  the  Greek  ^eJUoc,  cork. 

f  It  appears  quite  certain  that  not  all  lenticels  develop  from  the 
hypoderma  beneath  stomata  ;  phellogen  forms  beneath  the  epider- 
mis at  other  points,  and  gives  rise  to  lenticela  in  a  way  essentially  as 
in  the  other  cases. 


THE  FUNDAMENTAL  SYSTEM. 


127 


(b)  Ordinary  herbaceous  Dicotyledons  furnish  the  best  examples  of 
fully  developed  fundamental  tissues  ;  they  can  be  most  easily  exam- 
ined after  soaking  for  some  time  in  alcohol. 

(e)  Examples  of  thin-walled  cork  are,  of  course,  best  obtained  from 


Fig.  113. — Transverse  section  through  a  lenticel  of  Betula  alba,  e,  e,  epidermis  ;  «, 
old  stoma  ;  under  this  i*  a  mass  of  cork  which  develops  from  the  phellogen  layer 
lying  next  to  the  ordinary  parenchyma  (figured  darker)  ;  the  great  multiplication  of 
cork-cells  has  pushed  out  the  epidermis.  X  280.— After  De  Bary. 

the  ordinary  commercial  article  ;  the  thick-walled  form  may  be  obtained 
from  the  bark  of  the  beech,  willow,  prickly  ash  (Xanthoxylnm  Amer- 
icanum),  Viburnum  opulm,  etc.  Its  development  may  be  observed  by 
making  successive  sections  of  the  shoots  at  different  heights. 


CHAPTER  VIII. 

INTERCELLULAR  SPACES   AND  SECRETION  RES- 
ERVOIRS. 

160. — In  addition  to  the  cavities  and  passages  which  are 
formed  in  the  plant  from  cells  and  their  modifications,  there 
are  many  important  ones  which  are  intercellular,  and  which 
at  no  time  were  composed  of  cells.  In  some  cases  they  so 
closely  resemble  the  cavities  derived  from  cells  that  it  is  with 
the  greatest  difficulty  that  their  real  nature  can  he  made  out. 
In.  their  simplest  form  they  are  the  small  irregular  spaces 
which  appear  during  the  rapid  growth  of  parenchyma-cells 
(Fig.  51,  p.  67) ;  from  these  to  the  large  regular  canals 
which  are  common  in  many  water  plants  there  are  all  inter- 
mediate gradations. 

161. — In  leaves,  especially  in  the  parenchyma  of  the  under 
portion,  there  are  usually  many  large  irregular  spaces  be- 
tween the  cells  ;  they  are  in  communication  with  the  exter- 
nal air  through  the  stomata,  and  contain  only  air  and  watery 
vapor.  The  petioles  and  stems  of  many  aquatic  plants  con- 
tain exceedingly  large  air- conducting  intercellular  canals, 
which  occupy  even  more  space  than  the  surrounding  tissues 
(Fig.  9,  page  20).  In  the  Water-lilies  (Nymphceacece)  and 
Water-plantains  (Alismacece]  they  are  so  large  as  to  be  read- 
ily seen  by  the  naked  eye,  and  in  the  Naiads  (\ni(i<I<t/Ttr) 
they  are  almost  equally  large  (Fig.  114).  In  the  fibre- vascu- 
lar bundles  of  Equisetum,  and  of  many  Monocotyledons  and 
some  Dicotyledons,  there  are  intercellular  canals,  sometimes 
of  very  considerable  diameter  (Figs.  99,  102,  103).  Lastly, 
in  the  medullary  parenchyma  (pith)  of  many  plants  there  is 
a  large  central  cavity  (although  formed  in  part  by  the  rup- 
ture of  some  cell-walls),  which  must  be  considered  as  inter- 


INTERCELL  ULAR  SPACES. 


129 


cellular ;  of  this  nature  are  the  cavities  in  many  hollow  stems 

e.g.,  in  many  Umbelliferse  and  Gramineae. 

162. — There  are  in  many  plants  intercellular  spaces  and 
canals,  which  are  made  the  receptacles  for  special  secretions, 
and  to  which  the 
name  of  Secretion 
Reservoirs  may  be 
applied.  They  are 
surrounded  ( at 
first,  at  least)  by 
secreting  cells, 
which  furnish  the 
oil,  gum,  resin,  and 
other  substances 
(seep.  62)  found  in 
the  reservoir  s. 
Their  structure 
and  mode  of  de- 
velopment may  be 
illustrated  by  the 
gum-canals  of  the 
Ivy  (Hedera  helix). 
Each  at  first  con- 
sists of  a  long  col- 
umn developed  in 
the  phloem,  and 
composed  of  four 
or  five  rows  of  thin- 
walled  cells  arrang- 
ed radially  about  a 

Common  axis.    The  Fig.  114.-Part  of  the  transverse  section  throneh  th» 
11                                4.  internode  of  the  stem  of  Potamogeton  pectinatite.  show- 
Cells  S0011    Separate  in?  the  large  intercellular  spaces   between  th-  central 
from  P'ipli  nthpr  in  fibro- vascular  bundle  and  the  circumference  of  the  stem  : 
IlOIIiedCn  Otliei   in  epidermis;  a,  a  small  handle.  consigns  of  mirronnd- 
thp  'ivis  nf  flip  nnl  ing  fibrous  tissue  and  a  vnry  s.ma'1  central  mas«  of  sieve 
*•  tissue:  b,  b.  b.  small  bundles  containing  only  fibrous  do- 
ll 11111        and         fhim  sue;  **•  hmidle  sheath  of  principal  hnndli'in  the  axis  of 
0  the  stem,  within  which  is  a  mass  of  sieve  tissue  surround- 
form  a  Small   Canal  ing  the  intercelllllar  canal,  g.     X  80. -After  DeBary. 

(Fig.  115,  A),  which  is  afterward  increased  in  diameter  by 
the  formation  of  radial  partitions,  and  the  tangential  growth 
of  the  surrounding  cells  (Fig.  115,  E}.  The  surrounding 


130 


BOTANY. 


cells  secrete  a  peculiar  sap  or  gum,  which  passes  into  and 
fills  up  the  canal. 

In  the  Coniferse  the  turpentine  canals  have  essentially  the 
same  structure.  They  are  found  in  the  bark,  wood  and  pith  ; 
they  occasionally  unite  with  one  another,  or  change  their 
direction  through  some  of  the  medullary  rays,  the  cells  of 
which  have  apparently  become  transformed  into  resin-secret- 
ing tissue. 

163.— Allied  to  the  foregoing,  although  formed  in  a 
slightly  different  way,  are  the  small  secretion  reservoirs  of 
many  plants,  and  in  which  oils,  resins,  gums,  and  other 


Fijr  115.— Transverse  sections  of  young  stem  of  Ivy  (ffedera  helix).  A,  young  i\ 
tercellular  gum  canal,  surrounded  by  four  cells  ;  c.  cambium  ;  wt>.  soil  hast  ;  E, 
fully  developed  canal,  g  ;  b,  bast ;  rp,  cortical  parenchyma,  x  800.- Aftur  Sachs. 

odorous  substances  are  collected.  The  fragrance  of  many 
fruits — e.g.,  oranges  and  lemons — is  due  to  the  oils  and  other 
matters  contained  in  such  Receptacles.  In  Dictamuiis  fra.r- 
inflla  these  are  developed  as  follows  :  two  mother-cells  (p,  p, 
Fig.  116)  appear  in  the  hypoderma  and  divide  by  several 
partitions,  forming  a  mass  of  thin-walled  secreting  cells 
(Fig.  116,  B) ;  these,  by  a  degeneration  of  their  walls,  fuse 
into  a  common  cavity  filled  with  oil  and  watery  matter  (Fig. 
116,  C).  It  appears  that  the  outer  layer  of  secreting  cells 
(c,  c)  is  developed  from  the  epidermis  (Fig.  116,  A,  d,  c); 
hence  this  is  partly  an  epidermal  structure. 

Of  like  nature  are  the  reservoirs  in  the  "glandular  hairs  " 
of  the  same  plant  ;  in  fact,  the  two  structures  are  apparently 


SECRETION  RE8ER  VOIRS. 


131 


but  slightly  different  developments  of  the  same  organ  (Fig. 
117). 

(a)  The  smaller  and  more  irregular  intercellular  spaces  may  be 
studied  in  the  fundamental  tissue  of  the  stem  of  Indian  corn,  in  the 
parenchyma  of  most  leaves,  and  the  stems  of  Juncm. 


FIG.  116. 


Fm.  117. 


Fig.  116.— Internal  glands  of  the  leaf  of  Dictamnw  fraxineUa.  A  and  B,  curly 
stages  of  development;  C,  mature  gland  ;  d,  epidermis  ;  c,  p,  mother-cells  of  the  ue- 
creting  cells  ;  o,  drop  of  ethereal  oil. — After  Rauter. 

Fig.  117.— Glandular  hair  of  the  inflorescence  of  Dictamnus  fraxineUa  ;  A  and  B, 
earliest  stages,  showing  the  origin  to  be  similar  to  that  of  the  internal  glands  ;  C,  fully 
developed  hair  ;  the  part  h  is  the  true  hair,  while  all  below  it,  including  the  oil  cav- 
ity, is  to  be  regarded  as  an  outgrowth  of  the  sub-epidermal  cells.  X  about  220.— After 
Rauter. 

(6)  Thin  cross-sections  of  the  etems  and  petioles  of  NymphcKfi, 
Nuphar,  Ndumbium,  Sagittaria,  Potamogeton,  and  many  other  water 
plants,  afford  excellent  specimens  for  the  study  of  intercellular  canals. 


132  BOTANY. 

The  relation  of  the  intercellular  spaces  of  the  leaves  to  the  canals  of 
the  petioles  may  be  studied  by  carefully  made  longitudinal  sections. 

(c)  The  resin  canals  of  Stttphium  laciniatum  and  S.  perfoliatum,  and 
the  turpentine  canals  of  Coniferae,  furnish  excellent  examples  of  the 
larger  secretion  reservoirs,  while  the  smaller  ones  may  be  studied  in 
the  cavities  in  the  rind  of  the  orange  and  lemon,  the  leaves  of  Dictam- 
mis,  Xanthox'ilum,  Rue  (Ruta),  Hypericum,  and  many  Labiatae. 


CHAPTER  IX. 

THE    PLANT-BODY. 

§  I.     GrENEEALIZED   FOKMS. 

164. — The  cells,  tissues,  and  tissue  systems  described  in 
the  preceding  pages  are  variously  arranged  in  the  different 
groups  of  the  vegetable  kingdom  to  form  the  plant-body. 
The  simplest  plants  are  single  cells  or  undifferentiated 
masses  of  cells ;  in  those  next  higher  the  cells  are  aggre- 
gated into  simple  tissues,  while  still  above  these  the  tissues 
are  grouped  into  tissue  systems.  With  this  internal  differ- 
entiation there  is  a  corresponding  differentiation  of  the  ex- 
ternal plant-body.  The  lower  plants  are  not  only  simpler  as 
to  their  internal  structure,  but  they  are  so  as  to  their  exter- 
nal form  as  well.  The  higher  plants  are  as  much  more 
complex  than  the  lower  ones  as  to  their  external  parts  as 
they  are  in  regard  to  their  tissues  and  tissue  systems. 

165. — In  the  lowest  groups  of  plants  the  simple  plant- 
body  has  no  members  ;  the  single-or  few-celled  alga  has  no 
parts  like  root,  stem,  or  leaf  ;  it  is  a  unit  as  to  its  external 
form.  In  the  higher  groups,  on  the  contrary,  the  plant- 
body  is  composed  of  several  to  many  less  or  more  distinct 
members.  In  those  plants  in  which  they  first  appear,  the 
members  are  not  clearly  or  certainly  to  be  distinguished  from 
the  general  plant-body  ;  but  in  the  higher  groups  they  be- 
come distinctly  set  off,  and  are  eventually  differentiated  into 
a  multitude  of  structural  and  functional  forms. 

166. — As  will  be  seen  in  the  future  chapters,  every  plant, 
in  its  earliest  (embryonic)  stages,  is  simple  and  memberless  ; 
and  every  member  of  any  of  the  higher  plants  is  at  first  indis- 
tinguishable from  the  rest  of  the  plant-body ;  it  is  only  in 


134  BOTANY. 

the  later  growth  of  any  member  that  it  becomes  distinct ;  in 
other  words,  every  member  is  a  modification  of,  and  develop- 
ment from,  the  general  plant-body.  Likewise,  where  equiva- 
lent members  have  a  different  particular  form  or  function, 
it  is  only  in  the  later  stages  of  growth  that  the  differences 
appear.  All  equivalent  members  are  alike  in  their  earlier 
stages,  whether,  for  example,  they  eventually  become  broad 
green  surfaces  (foliage  leaves),  bracts,  scales,  floral  envelopes, 
or  the  essential  organs  of  the  flower. 

167. — These  facts  make  it  necessary  to  have  some  general 
terms  for  the  parts  of  the  plant-body,  which  are  applicable 
to  them  in  all  their  forms.  We  must  have,  for  example,  a 
term  so  generalized  as  to  include  foliage  leaves,  bracts,  scales, 
floral  envelopes,  and  all  the  other  forms  of  the  so-called  leaf- 
series.  So,  too,  there  is  need  of  a  term  to  include  stems, 
bulbs,  bud,  and  flower  axes,  root-stocks,  corms,  tubers,  and 
the  other  forms  of  the  so-called  stem-series. 

168. — By  a  careful  study  of  the  members  of  the  more 
perfect  plants  we  find  that  they  may  be  reduced  to  four 
general  forms,  viz.,  (1)  Caulome,  which  includes  the  stem 
and  the  many  other  members  which  are  found  to  be  its 
equivalent ;  (2)  Phyllome,  including  the  leaf  and  its  equiva- 
lents ;  (3)  Trichome,  which  includes  all  outgrowths  or  ap- 
pendages of  the  surface  of  the  plant,  as  hairs,  bristles,  root- 
hairs,  etc.  ;  (4)  the  Root,  which  includes,  besides  ordinary 
subterranean  roots,  those  of  epiphytes,  parasites,  etc. 

169. — As  indicated  above,  in  the  lower  plants  the  differ- 
entiation into  members  is  not  so  marked  as  in  the  higher, 
and  in  passing  downward  in  the  vegetable  kingdom  groups 
are  reached  in  which  it  is  inappreciable,  and  finally  in  which 
it  is  entirely  wanting  ;  such  an  undifferentiated  plant-body 
is  called  a  Thallome,  and  may  properly  be  regarded  as  the 
original  form,  or  prototype. 

17O. — Thallome.*  The  simplest  thallome  is  the  single 
'cell ;  this,  though  generally  rounded,  is,  in  some  cases 
(Botrydium,  Caulerpa,  etc.),  irregularly  extended  into 
branch-like  or  leaf-like  portions,  which  must  not  be  mistaken 

*  From  the  Greek  t?a//i)9,  a  young  shoot,  branch,  or  frond. 


GENERALIZED  FORMS.  135 

for  members  coordinate  with  those  mentioned  above,  as  they 
are  only  parts  of  a  unit,  instead  of  members  of  a  body ;  they 
may  be  regarded  as,  to  a  certain  extent,  foreshadowings  or 
anticipations  of  the  members  of  the  higher  plants.  Plants 
composed  of  rows  of  cells  or  cell  surfaces  frequently  show 
no  indication  whatever  of  a  division  into  members  ;  but,  in 
some  cases,  there  is  a  little  differentiation,  which,  though 
[not  carried  far  enough  to  give  rise  to  members,  is  the  same 
in  kind.  In  the  larger  algae  there  is  sometimes  so  much  of 
a  differentiation  that  it  becomes  difficult  to  say  why  certain 
parts  ought  not  to  be  called  members.  Caulome  and  phyl- 
lome,  at  least,  are  strongly  hinted  at  in  the  Fucaceae,  and 
in  this  group,  although  the  term  thallome  is  applied  to  the 
plant-body,  it  must  be  admitted  as  not  fully  applicable. 
Structures  of  this  kind  are  instructive,  as  showing  that  the 
passage  from  the  thallome  plant-body  to  that  in  which 
members  are  differentiated  is  by  no  means  an  abrupt  or 
sudden  one. 

171.— Mutual  Relations  of  Thallome,  Caulome,  and 
Phyllome.  The  caulome  is  the  phyllome-bearing  axis  of  the 
plant,  and  phyllomes  are  the  members  developed  upon  the 
caulome.  The  two  have  a  reciprocal  relation,  and  in  no 
case  is  the  one  present  without  the  other.  The  definition  of 
the  one  involves  that  of  the  other.  Both  are  derived 
directly  from  the  thallome,  and  that  differentiation  which 
gives  rise  to  one  necessarily  produces  the  other.  The  differ- 
entiation of  thallome  into  caulome  and  phyllome  is  simply 
a  lobing  and  contraction  of  the  marginal  portions  into  sepa- 
rable phyllomes,  and  a  rounding  and  contraction  of  the 
central  or  axial  portion  into  a  caulome. 

172. — Caulome.*  By  this  general  name  we  designate 
all  axial  members  of  the  plant.  In  the  more  obvious  cases 
the  caulome  is  the  axis  which  bears  leaves  (foliage),  and  in 
this  form  it  constitutes  (1)  the  Stem;  branches  are  only  stems 
which  originate  laterally  upon  other  stems. 

The  other  caulome  forms  are  : 

(2.)  Runners,  which  are  bract-bearing,  slender,  weak,  and 
trailing. 

*  From  the  Greek  xniv.oS,  stem. 


136  BOTANY. 

(3.)  Root-stocks,  which  are  bract  or  scale-bearing,  usually 
weak,  and  subterranean. 

(4.)  Tubers,  which  are  bract  or  tcale-bearing,  short  and 
thickened,  and  subterranean. 

(5.)  Corms,  which  are  leaf -bearing,  short  and  thickened, 
and  subterranean. 

(6.)  Bulb-axes,  which  are  leaf-bearing,  short  and  conical, 
and  subterranean. 

(7.)  Flower-axes,  which  are  bract,  perianth,  stamen,  and 
pistil-bearing,  short,  and  usually  conical  and  aerial. 

(8.)  Tendrils,  which  are  degraded,  slender,  aerial  cau- 
lomes,  nearly  destitute  of  phyllomes. 

(9.)  Thorns,  which  are  degraded,  thick,  conical,  aerial 
caulomes,  nearly  destitute  of  phyllomes. 

173. — Phyllome.*  The  phyllome  is  always  a  lateral 
member  upon  a  caulome.  It  is  usually  a  flat  expansion  and 
extension  of  some  of  the  tissues  of  the  caulome.  Its  most 
common  form  is  (1)  the  Leaf  (foliage),  which  is  usually  large, 
broad,  and  mainly  made  up  of  chlorophyll-bearing  paren- 
chyma. 

The  other  phyllome  forms  are  : 

(2.)  Bracts,  which  are  smaller  than  leaves,  generally  green. 

(3.)  Scales,  which  are  usually  smaller  than  leaves,  wanting 
in  chlorophyll-bearing  parenchyma,  and  with  generally  a 
firm  texture. 

(4.)  Floral  envelopes,  which  are  variously  modified,  but 
generally  wanting  in  chlorophyll-bearing  parenchyma,  and 
with  generally  a  more  delicate  texture. 

(5.)  Stamens,  in  which  a  portion  of  the  parenchyma  de- 
velops male  reproductive  cells  (pollen). 

(6.)  Carpels,  bearing  or  enclosing  female  reproductive 
organs  (ovules). 

(7.)  Tendrils  and  Spines,  which  are  reduced  or  degraded 
forms,  composed  of  the  modified  fibro-vascular  bundles,  and 
a  very  little  parenchyma  ;  in  the  first  the  structures  are  weak 
and  pliable,  in  the  latter  stout  and  rigid. 

The  altogether  special  modifications  of  the  phyllome,  as  in 
pitchers  and  cups,  will  be  noticed  hereafter. 

*  From  the  Greek  fvMav,  leaf. 


GENERALIZED  FORMS.  13? 

174. — Trichome.*  The  trichome  is  a  surface  appendage 
consisting  of  one  or  more  cells  usually  arranged  in  a  row  or 
a  column,  sometimes  in  a  mass.  Its  most  common  forms  are 
met  with  in  (1)  the  Hairs  of  many  plants.  (See  page  95.) 

The  other  trichome  forms  are  : 

(2.)  Bristles,  each  consisting  of  a  single  pointed  cell  or 
a  row  of  cells,  whose  walls  are  much  thickened  and  hardened. 

(3.)  Prickles,  like  the  last,  but  stouter,  and  usually  com- 
posed of  a  mass  of  cells  below. 

(4.)  Scales,  in  which  the  terminal  cell  gives  rise  by  fission 
to  a  flat  scale,  which  soon  becomes  dry. 

(5.)  Glands,  which  are  generally  short,  bearing  one  or 
more  secreting  cells. 

(6.)  Root-hairs,  which  are  long,  thin,  single-celled  (in 
mosses  a  row  of  cells),  and  subterranean. 

(7.)  Sporangia  of  Pteridophytes,  some  of  whose  interior 
cells  develop  into  reproductive  cells  (spores). 

(8.)  Ovules  of  Phanerogams,  one  or  more  of  whose  cells 
develop  into  reproductive  cells  (embryo  sacs).f 

175.— Root.  The  root  is  that  portion  of  the  plant-body 
which  is  clothed  at  its  growing  point  with  a  root-cap.  In 
ascending  through  the  vegetable  kingdom  roots  are  the 
latest  of  the  generalized  forms  to  make  their  appearance, 
and  in  the  embryo  they  appear  to  be  formed  later  than 
caulome  and  phyllome.  They  present  fewer  variations  than 
any  of  the  other  generalized  forms.  The  ordinary  (1)  Sub- 
terranean roots  of  plants  are  typical.  They  differ  but  little 
from  one  another  in  all  the  groups  of  the  Pteridophytes  and 
Phanerogams. 

The  other  root  forms  are  : 

(2.)  Aerial  roots,  Avhich  project  into  the  air,  and  often  have 
their  epidermis  peculiarly  thickened,  as  in  the  epiphytic 
orchids. 

(3.)  Roots  of  Parasites,  which  are  usually  quite  short,  and 


*  From  the  Greek  tfp/'f,  rpn;6s,  a  hair. 

f  It  is  held  by  some  botanists  that  in  some  plants  the  ovule  is  "the 
terminal  portion  of  the  axis,"  and  that  in  others  it  is  a  leaf  or  part  of  a 
leaf. 


138 


BOTANY. 


in  some  cases  provided  with  sucker-like  organs,  by  means  of 
which  they  come  into  a  more  intimate  relation  to  their  hosts. 

176.— Particular  Relations  of  Phyllome  to  Caulome. 
Sachs*  has  formulated  the  relations  of  phyllome  to  caulome 
in  substance  as  follows  : 

(1. )  Phyllomes  always  originate  from  the  Primary  Meris- 
tem  of  the  punctum  vegetationis  ;  fully  differentiated  tissues 
are  incapable  of  producing  them. 

(2.)  They  are  always  exogenous  formations  ;  that  is,  they 


FIG.  119. 


FIG.  118. 


Fig.  118. — Diagrams  of  dichotomous  branching.    A,  normal  dichotomy,  in  which 
ch  branch  is  again  dichotomonaly  branched  ;  B,  helicoid  dichotomy,  i 
right-hand  branch,  r,  does  not  develop  further,  while  the  left-hand  one,  I,  is  in  every 


case  again  branched  ;  C,  scorpioicl  dichotomy,  in  which  the  branc 
further  developed. — After  Sacns. 

Fig.  119.— Diagram  of  botryose  monopodial  branching.    The  numerals  indicate  the 
'•generations.'' 

develop  from  outer  and  not  inner  tissues,  consequently  their 
tissues  are  externally  continuous  with  those  of  the  caulome. 
(3.)  They  always  originate  below  the  growing  apex  of  the 
caulome  as  lateral  outgrowths  ;  they  may  appear  singly,  so 
that  no  two  are  situated  at  the  same  height  on  the  stem,  or 
two  or  more  may  grow  at  once,  generally  at  equal  distances 
from  one  another  in  the  circumference  of  the  caulome. 


*"  Text-Book,"  p.  181. 


GENERALIZED   FORMS. 


139 


(4.)  They  always  arise  in  acropetal*  order. 

(5.)  They  grow  more  rapidly  than  the  caulome  does  above 
their  insertion.  When  they  are  numerous  their  rapid  growth 
gives  rise  to  the  accumulation  of  phyllomes  known  as  a  Bud. 

(6.)  The  phyllomes  of  any  plant  are  always  of  a  different 
form  than  the  caulomes. 

177.— General  Modes  of  Branching  of  Members.  There 
are  two  general  modes  of  the  branching  of  the  members  of 
the  plant-body.  In  the  one,  the  apex  of  the  growing  mem- 
ber divides  into  two  new  growing  points,  from  which  branches 
proceed ;  this  is  the  Dichotomous  mode  of  branching  (Fig. 


\ 


Pig.  120.— Diagrams  of  cymose  monopodial  branching.    A  and  B,  scor. 
C,  forked  cymose  monopodium.  the  compound  or  falsely  dichotomous  cyme  I 
also  the  dicnasium)  •  D,  helicoid  cyme. — After  Sachs. 

118).  In  the  other,  the  new  growing  points  arise  as  lateral 
members,  while  the  original  apex  of  the  parent  stem  still 
retains  its  place  and  often  its  growth  ;  this  is  the  Mono- 
podial mode  of  branching  (Fig.  119).  Both  modes  are  sub- 
ject to  many  modifications,  the  most  important  of  which  are 
briefly  indicated  in  the  following  table  : 

A.— DICHOTOMOUS. 

1.  Forked  dichotomy,  in  which  both  branches  of  each  bifurcation  are 
equally  developed  (Fig.  118,  A). 

*  Acropetal,  tending  toward  the   summit;   fr>in  the  Greei    £*,>a. 
summit,  and  nerda,  to  move  toward. 


140  EOT  ANT. 

2.  ttympodM  dichotomy,  in  which  one  of  the  branches  of  each  bifur- 
cation develops  more  than  the  other. 

a    Helicoid  *ympodial  dichotomy,  in  which  the  greater  development 

is  always  on  one  side  (Fig.  118,  B). 

b.  Scorpioid  sympodiul  dichotomy,   in  which  the  greater  develop- 
ment is  alternately  on  one  side  and  the  other  (Fig.  118,  G). 

B.— MONOPODIAL. 

1.  Botryose  monopodium,  in  which,  as  a  rule,  the  axis  continues  to 
grow,  and  retains  its  ascendency  over  its  lateral  branches  (Fig.  1 19). 

2.  Cymose  monopodium,  in  which  the  axis  soon  ceases  to  grow,  and  is 
overtopped  by  one  or  more  of  its  lateral  brandies. 

a.  Forked  cymose  monopodium,  in  which  the  lateral  branches  are 

all  developed  (Fig.  120,  G). 

b.  Sympodial  cymose  monopodium,   in  which  some  of  the  lateral 

branches  are  suppressed  ;  this  may  be 
6'.  Helicoid,  when  the  suppression  is  all  on  one  side  (Fig.  120, 

D);  or 
b".  Scorpioid,  when  the  suppression  is  alternately  on  one  side 

and  the  other  (Fig.  120,  A  and  B). 

Dichotomous  branching  takes  place  in  many  Thallophytes ;  it  is 
beautifully  seen  in  the  appendages  to  the  perithecia  of  many  Erysipha- 
cese  (e.g.,  lilac-blight,  cherry- blight,  etc.)  It  occurs  also  in  the  roots, 
stems,  and  leaves  of  many  Pteridophytes,  and  the  leaves  and  other 
phyllome  structures  of  some  Phanerogams. 

Monopodial  branching  is,  on  the  other  band,  the  general  rule  for  all 
members  of  the  plant-body  in  Phanerogams,  and  in  Pteridophytes, 
Bryopbyte&,  and  Thallophytes  very  much  of  the  branching  is  also  of 
this  kind.* 

§  II.    STEMS. 

178. — The  primary  stem  of  a  plant  first  develops  from  the 
meristem  tissue  of  the  embryo ;  its  subsequent  growth  is  a 
growth  from  the  meristem  of  the  punctum  vegetationis,  to- 
gether with  an  intercalary  growth  of  its  newer  parts.  On 
account  of  the  more  rapid  growth  of  its  young  leaves,  it  usu- 
ally happens  that  the  stem  is  terminated  by,  and  appears  to 
grow  from,  a  bud  ;  m  fact,  it  is  a  common  statement  that 
stems  grow  from  buds.  It  will  be  necessary  to  examine  the 
bud  in  detail. 

*  A  full  discussion  of  this  subject  would  occupy  more  space  than  can 
be  allotted  to  it  in  this  book,  and  any  attempt  to  cover  the  subject  in  a 
1'ew  pages  would  tend  rather  to  confuse  the  student  than  to  enlighten 
him.  For  a  good  account,  the  student  is  referred  to  Sachs'  "  Text-Book 
of  Botany,"  p.  155 ;  Hofmeister's  "  Allgerneiiie  Morphologic  der  Ge- 


STEMS. 


141 


179. — Tliepunctum  vegetationis  (growing  point)  of  a  stem 
is  generally  a  conical  point ;  upon  its  curved  surface  a  little 
below  its  apex  the  rudiments  of  leaves  appear  as  slight  swell- 
ings or  papillae ;  as  the  growing  point  elongates,  and  the 
rudimentary  leaves  grow,  new  ones  appear  above  the  pre- 
viously formed  ones.  By  the  more  rapid  growth  of  the 
leaves  than  the  newer  part  of  the  stem,  the  latter  comes  to 
be  covered  with  many  closely  approximated  young  leaves. 
This  is  the  usual  condition  of  the  ends  of  growing  stems  in 
summer,  hence  such  an  aggre- 
gation of  rudimentary  leaves 
may  be  termed  a  summer 
bud.  While  in  the  apex  of 
the  bud  the  leaves  grow  more 
rapidly  than  the  stem,  in  its 
base  the  growth  of  the  stem 
is  much  the  most  rapid.  This 
later  stem-growth  is  an  inter- 
calary one,  and  it  results  in 
separating  the  previously  ap- 
proximated leaves  a  consid- 
erable distance  from  one 
another,  forming  the  inter- 
nodes  of  the  stem. 

180.  —  Winter  buds  have 
essentially  the  same  struc- 
ture, and  the  same  mode  of 
formation.  In  these,  how- 
ever, most  of  the  phyllome 
rudiments  develop  into  more 
or  less  hardened  scales,  which 
grow  rapidly  and  overtop  the  punctum  vegetationis.  The 
basal  growth  of  the  bud  ceases,  and  soon  its  apical  growth 
also,  and  thus  the  scaly  phyllomes  are  left  in  close  approxi- 
mation (Fig.  121).  Such  a  bud  is  but  a  state  of  the  ter- 
minal portion  of  the  leaf-bearing  stem,  and  not  a  new  for- 
mation or  member ;  it  cannot  even  be  called  an  organ. 

181, — Upon  the  return  of  warm  weather  in  the  spring 


Fig.  121.— Extremity  of  a  branch  of  the 
Horse-chestnut  (JEsculvii  hippocastanitm); 
a  large  terminal  bud  with  two  smaller  lat- 
eral buds  ;  a,  a,  a,  scars  of  fallen  leaves. 
Natural  size.— After  Diichartre. 


wachse,"  p.  432,  and  Eichler's  "  Bliithendiagramme,"  page  33  et  seq. 
In  each  there  are  many  references  given  to  the  literature  of  the  subject. 


142 


BOTANY. 


the  basal  growth  of  the  bud  is  resumed,  and  shortly  after- 
ward, or  simultaneously,  the  apical  growth  also.  The  thick 
scales  separate  by  the  slight  elongation  of  the  stem,  and  being 
of  no  further  use  to  the  plant  they  soon  fall  off.  The  inter- 
calary growth  of  the  scale-bearing  portion  of  the  stem  is  gen- 
erally much  less  than  of  that  which  bears  leaves,  hence  the 
first  internodes  which  appear  in  the  spring  of  the  year  are 
quite  short.  The  punctum  vegetatiouis  of  such  a  winter 
bud,  after  resuming  its  activity,  goes  on  developing  leaves  as 
lateral  members  exactly  as  if  there  had  been  no  interruption 
in  its  activity.  Upon  the  approach  of  autumn  again  the 


Fig.  122. — Longitudinal  section  of  the  apex  of  the  stem  of  a  moss  (Fontinalis  anti- 
pyretica).  •»,  apical  cell  ;  a,  outer  part  of  one  of  the  segments  cut  off  from  apical 
cell ;  «,  apical  cell  of  a  lateral  leaf-h.-arin?  shoot  arising  below  a  leaf;  c,  firet  cell  or 
a  leaf ;  b,  b,  cells  forming  cortex  -After  Leitgeb. 

same  process  of  bud-formation  takes  place  by  the  decrease  in 
the  rapidity  of  extension,  and  its  final  cessation  ;  this  is  fol- 
lowed again  by  the  resumption  of  growth  upon  the  advent  of 
spring.  Thus  the  stem  exhibits  a  periodicity  in  its  growth, 
and  one  of  its  phases  is  the  so-called  winter  bud. 

182. — Branches  of  stems  (lateral  stems)  normally  originate 
in  the  pnnctum  vegetationis  as  lateral  outgrowths  (Fig. 
122,  z) ;  each  develops  first  into  a  conical  mass,  which  then 
becomes  the  punctum  vegetationis  of  a  new  stem,  and  upon 
it  lateral  members  arise,  as  in  the  case  of  the  principal  stem. 
The  new  stem  may  elongate  at  once  into  a  leafy  shoot,  as 


STEMS. 


143 


takes  place  in  annuals  ;  on  the  other  hand,  it  may  make  but 
little  growth  in  extension,  so  forming  a  bud,  as  is  common 
in  perennials  (Fig.  123).  Buds  like  the  last,  which  are 
apparently  sessile  upon  the  parent  axis,  are  said  to  be  lateral, 
although,  strictly  speaking,  they  are 
terminal  upon  very  short  stems. 

183.  —  It  most  frequently  hap- 
pens that  new  stems  arise  near  to 
certain  leaves.  The  origin  of  the 
stem  may  be  below  the  leaf,  as  in 
many  Bryophytes  (z,  Fig.  122)  ;  or 
beside  it,  as  in  Equisetacese  ;  or 
above  it  in  its  axil,  as  in  Monocoty- 
ledons and  Dicotyledons  (Fig.  121), 
and  it  appears  that  in  each  case  the 
new  stern  originates  shortly  after 
the  leaf. 

184.  —  In     Monocotyledons     and 
Dicotyledons    there  are  usually  as 
many  new  stems   formed  as   there 
are  leaves  ;  exceptionally  there  may 
be  several  new  stems  (supernumer- 
ary stems  or  buds)  formed  in  the 
axil  of  .each    leaf  (Fig.   123.)     In 
mosses,  ferns,  and  Conifers,  on  the 
contrary,  there  are  by  no  means  as 
many  new  stems  as  there  are  leaves. 

185.  —  Rarely,  new  stems  (adven- 
titious  stems  or  buds)  arise  from 
the  older  parts  of  plants  ;  thus  they 
may  arise  from  petioles  and  ribs  of 
some  leaves  —  e.g.,    Begonia,   Bryo- 
pli  i/llum,  etc.  ;  from  the  cambium  of 
the    cut  surfaces  of   stems  -e.g., 
elm,  willow,  etc.;  and  sometimes  in 

abundance    from    the    fibrO-VaSClllar 

bundles  of  roots  —  e.g.,  Populus  alba,  cherry,  sweet  potato, 
etc.  Such  structures  are  always  endogenous,  as  in  all  cases 
they  spring  from  some  portion  of,  or  near  to,  the  fibro-vas- 
cular  bundles,  and  break  through  the  overlying  tissues. 


ural  size.—  After  Duchartre. 


144  SO TAN T. 

186. — Frequently  the  new  stems  which  are  normally  formed 
make  but  a  very  little  growth,  and  in  perennials  become 
covered  by  the  subsequently  formed  tissues  ;  they  thus  become 
the  so-called  dormant  buds.  Under  favorable  conditions  they 
may  resume  their  growth  long  afterward,  and  they  are  then 
liable  to  be  mistaken  for  adventitious  stems.  Probably  very 
many  of  the  supposed  cases  of  adventitious  stems  upon  the 
older  stems  of  Dicotyledons  are  in  reality  only  the  late 
growths  of  stems  which  have  been  dormant  for  a  long  time. 

(si)  The  development  of  stems  may  be  studied  in  almost  any  plant. 
Those  which  have  large  winter  buds,  however,  offer  some  advantages 
to  the  beginner.  Such  are  the  buds  of  hickory,  horse-chestnut,  lilac, 
etc. 

(6)  Vertical  sections  should  be  made  of  the  buds  before  they  resume 
their  growth  in  the  spring,  and  these  should  be  compared  with  similar 
sections  made  after  some  growth  has  taken  place. 

(c)  Many  of  the  common  annuals  with  a  continued   growth — e.g., 
balsam,  mallow,  etc. — may  be  profitably  studied  for  making  out  the 
growth  of  summer  buds.     The  young  shoots  of  many  shrubs — e.g. , 
elder  and  lilac — are  also  excellent  for  study. 

(d)  Thin  enough  longitudinal  sections  should  be  made  to  show  the 
punctum  vegetationis.     The  specimens  may  often  be  made  much  more 
instructive  by  coloring  with  carmine,  or  other  staining  fluids. 

§  III.    OF  LEAVES  IN  GENERAL. 

187. — Every  leaf  originates  in  the  Primary  Meristem  of 
the  punctum  vegetationis.  It  is  at  first  a  small  projection 
or  papilla,  composed  of  one  or  more  cells,  which  undergo  a 
rapid  division,  thereby  producing  the  quick  early  growth 
before  mentioned  (p.  139).  Generally  the  multiplication  of  the 
cells  is  such  as  to  give  rise  to  a  surface  whose  plane  cuts  the 
stem  transversely.  In  many  cases  the  apex  of  the  leaf  soon 
becomes  changed  into  permanent  tissue  while  the  base  con- 
tinues to  grow,  indefinitely  in  grasses  and  many  other 
Monocotyledons,  and  definitely  in  most  Dicotyledons.  In 
other  cases  the  base  passes  over  into  permanent  tissue,  while 
the  apical  portions  keep  on  growing,  as  in  ferns  and  some 
pinnate  leaves  of  Dicotyledons. 

188. — Many  leaves  are  raised  upon  a  stalk  by  a  subsequent 
growth  between  the  stem  and  the  base  of  the  leaf  ;  this  leaf- 


OF  LEAVES  IN  GENERAL.  U5 

stalk  (petiole)  is  much  extended  in  the  lower  leaves  Of  many 
plants,  especially  of  those  which  grow  in  the  shade  or  are 
intermixed  with  other  plants.  Structurally  the  petiole  is  the 
extension  of  the  fibre-vascular  and  parenchymatous  connec- 
tion between  the  leaf  and  the  stem  ;  and  it  generally  forms 
an  articulation  or  joint  with  the  stem  at  its  lower  extremity  ; 
physiologically  it  is  a  support  for  the  leaf,  and  it  is  longer  or 
shorter  just  as  elongation  or  want  of  it  places  the  leaf  under 
the  best  physiological  conditions. 

189. — The  leaf  is,  when  first  formed,  destitute  of  fibro-vas- 
cular  bundles,  and  this  is  the  permanent  condition  of  the  leaves 
of  Bryophytes,  and  the  leaf -like  portions  of  the  Thallophytes. 
In  most  higher  plants,  however,  portions  of  the  leaf  tissue 
early  become  differentiated  into  one  or  more  fibro- vascular 
bundles,  which  pass  downward  into  the  stem  and  unite 
with  the  older  bundles  ;  the  upper  parts  of  the  bundles  grow 
with  the  leaf,  and  form  lateral  branches  and  branchlets, 
giving  rise  to  the  complicated  system  of  so-called  veins  so 
often  to  be  seen  (especially  in  Dicotyledons).  In  many  of 
the  smaller  phyllome  structures,  as  scales,  bracts,  etc.,  which 
may  be  regarded  as  rudimentary  leave *,  there  are  no  fibro- 
vascular  bundles,  just  as  in  the  rudiments  of  actual  leaves. 

190.—  Venation.  In  mosses  and  other  plants  destitute  of 
fibre-vascular  bundles,  the  veins,  when  present,  are  composed 
of  but  slightly  modified  parenchyma  ;  in  higher  plants  they 
are  composed  of  fibro-vascular  bundles  and,  in  the  larger 
veins,  of  one  or  more  surrounding  layers  of  modified  paren- 
chyma in  addition.  The  disposition  of  the  veins  in  a  leaf 
depends  largely  upon  its  mode  of  growth.  Usually  several 
veins  form  early ;  if  they  grow  from  a  common  point,  an 
arrangement  like  that  in  the  maple  (radiate  venation)  is  the 
result ;  if  the  veins  grow  from  points  on  an  axis,  the  various 
modifications  of  the  pinnate  venation  are  produced,  depend- 
ing upon  the  amount  of  elongation  of  the  axis. 

In  many  Monocotyledons  the  leaves  continue  to  gi*ow  at 
their  bases  ;  their  veins  are,  as  a  consequence,  parallel  with 
the  leaf  axis  ;  in  other  Monocotyledons  and  most  Dicoty- 
ledona  the  veins  originate  on  an  extending  axis,  and  pass 
outward  to  or  near  to  the  margins. 


146 


BOTANY. 


101. — Leaves  are  for  the  most  part  bilaterally  symmetrical, 
a  vertical  plane  passing  from  base  to  apex  generally  dividing 
them  into  two  equal  and  corresponding  halves.  In  the  elm, 
linden,  begonia,  etc.,  and  the  leaflets  of  many  compound 
leaves,  the  two  halves  are  unequal.  The  asymmetry  is  ap- 
parently related  in  some  way  to  the  position  of  the  leaves  on 
the  stem,  as  it  is  more  frequently  noticed  on  plants  whose 
leaves  are  two-ranked,  with  the  leaf  planes  parallel,  or 
nearly  so,  to  the  axis  of  the  stem  (or  in  compound  leaves,  to 
the  central  leaf  axis).  In  some  two-ranked  leaves  the  upper 
half  of  each  leaf  (i.e.,  that  nearer  to  the  apex  of  the  stem) 
is  the  larger,  while  in  others  the  opposite  is  the  case.* 

192. — In  form  leaves  are  very 
variable  ;  even  in  the  same  plant 
it  rarely  happens  that  all  have 
the  same  form.  In  general, 
elongated  forms  (i.e.,  linear  and 
oblong)  prevail  in  the  Monocoty- 
ledons, while  as  a  rule  they  are 
considerably  broadened  (i.e., 
lanceolate,  elliptical,  cordate, 
etc.)  in  mosses,  ferns,  and  Di- 
cotyledons ;  many  exceptions, 
however,  occur. 

193. — The  absolute  size  of 
leaves  varies  greatly  also.  The 
largest  leaves — as,  for  example,  those  of  palms,  tree-ferns,  ba- 
nana, Victoria  regia,  etc. — occur  in  the  warmer  portions  of 
the  earth  ;  in  frigid  regions  the  leaves  are  small ;  in  tem- 
perate climates  perennial  leaves  are,  as  a  rule,  smaller  than 
annual  ones. 

*  See  an  article  on  this  subject  by  Professor  Beal  in  American 
Natu-nli8t,  1871,  p.  571,  and  a  still  earlier  one  by  Dr.  Wilder.  Both 
writers  show  that  in  many  cases  the  upper  half  of  the  leaf  is  the  most 
devel9ped,  in  opposition  to  De  Candolle,  who  makes  the  statement 
that  "  the  side  most  developed  is  always  the  lower."  Herbert  Spencer's 
supposition  that  the  want  of  symmetry  is  (in  some  cases)  due  to  the 
shading  of  the  smaller  half  of  the  leaf,  they  show  not  to  be  correct,  as 
the  asymmetry  is  observable  in  the  voung  leaves  in  the  unexpanded 
budl 


Fig.  124.— A,  leaf  with  serrate  mar- 
gin ;  S,  leaf  with  dentate  or  toothed 
margin  ;  0,  leaf  with  crenate  or  scal- 
loped margin 


OF  LEA  VE8  IN  GENERAL. 


147 


194.— Leaves,  like  other  members  of  the  plant-body,  may 
branch  during  their  growth.  At  first  they  are  always  simple, 
and  if  the  growth  is  uniform  the  result  is  a  simple  leaf  ;  if, 
however,  as  frequently  happens,  the  growth  is  more  rapid  at 
certain  points,  branches  may  arise,  as  in  the  so-called  com- 
pound leaves.  All  grada- 
tions are  observable  between 
simple  leaves,  in  which  the 
growth  has  been  absolutely 
uniform  (producing  entire 
margins),  to  compound  . 
leaves  with  jointed  leaflets.  ( 
The  differentiation  is  here 
much  like  that  which  takes 

place    in    passing    from     the       Fig'  ^--Three-lobed  leaf  of  Hepatica. 

thallome  to  the  form  of  plant-body  with  distinct  caulome 
and  phyllome. 

The  simplest  cases  are  those  in  which  the  branches  are 
rudimentary,  as  in  the  serrate  (Fig.  124,  A),  dentate  (Fig. 
124,  B),  crenate  (Fig.  .124,  C],  and  other  similar  forms. 
When  the  branches  are  more  prominent  they  give  rise  to 
lobes  of  various  kinds  (Figs.  125,  126).  Where  the  longitu- 
dinal growth  of  the  leaf  (not  of  its 
brandies)  is  but  little,  the  lobes  ap- 
pear to  radiate  from  a  common 
point,  as  in  hepatica,  mallow,  maple, 
etc. ;  such  are  called  radiately,  pal- 
mately,  or  digitately  lobed.  Where, 
as  in  the  oak,  the  longitudinal 
growth  of  the  leaf  is  considerable, 
the  lobes  are  laterally  arranged  upon 
*  central  portion  ;  such  leaves  are 
said  to  be  pinnately  lobed. 

195. —  Leaf-brunches  frequently  become  so  developed  that 
they  themselves  form  distinct  leaves,  and  thus  we  have  what 
is  termed  the  compound  leaf  (Figs.  127  and  128).  Terms 
similar  to  those  used  in  the  case  of  lobed  leaves  are  here 
used  also  ;  thus  where  the  secondary  leaves  (leaflets)  grow 
from  an  extremely  short  axis,  so  that  they  radiate  from  a 


148 


BOTANY. 


common  point,  the  leaf  is  said  to  be  radiately,  palmately,  or 
digitately  compound  (Fig.  127,  A  and  £).  In  those  cases 
where  the  leaflets  grow  from  an  axis  which  lengthens  more 


Fig.  127.— .4,  pall 
compound  leaf. 


lately  compound  leaf  of  Horse-chestnut;  2?,  palmately  trifoliate 


or  less,  the  leaf  is  termed  a  pinnately  compound  one  (Fig. 
128,  A  and  B}.  It  not  infrequently  happens  that  in  the 
growth  of  leaflets  they  also  produce  branches,  giving  rise 
thus  to  doubly  compound  leaves. 


Fig.  Is28  —  A,  pinnately  compound  leaf  ;  B,  pinnately  compound  leaf,  with  common 
midrib  prolonged  and  metamorphosed  into  a  tendril.    (See  page  136.) 

196. — The  stipules  which  occur  as  lateral  appendages  upon 
the  petioles  of  many  leaves  of  Dicotyledons  are  early  leaf- 
branches  which  were  not  carried  up  by  the  subsequent  eloii- 


THE  ARRANGEMENT  OF  LEAVES.  149 

gation  of    the    petiole ;   as   in  the  pea,    vetch,   agrimony, 
quince,  etc. 

§  IV.    TUE  ARRANGEMENT  OF  LEAVES  (PHYLLOTAXIS). 

197. — Leaves  are  disposed  on  stems  in  various  ways  : 

(1.)  They  may  be  in  whorls  of  three  or  more  encircling 
the  stem  at  intervals.  In  this  case  each  whorl  was  formed  as 
a  ring  of  rudimentary  leaves  about  the  punctum  vegetationis.* 
The  leaves  of  each  succeeding  whorl  usually  appear  just 
above  and  between  the  preceding  ones,  so  that  the  whorls 
alternate  with  one  another. 

(2.)  Where  two  leaves  originate  on  exactly  opposite  sides 
of,  and  at  the  same  height  on,  the  punctum  vegetationis,  the 
opposite  arrangement  is  produced.  Here,  as  in  whorled 
leaves,  the  new  ones  usually  arise  in  the  intervals  between 
the  previously  formed  ones,  so  that  the  pairs  of  leaves  decus- 
sate. 

(3.)  If  the  leaves  originate  singly  (scattered  or  alternate 
leaves),  the  simplest  case  is  that  in  which  each  succeeding 
leaf  appears  a  little  above  the  preceding  and  on  the  opposite 
side  of  the  punctum  vegetationis.  In  this  case,  where  the 
stems  elongate,  the  leaves  are  arranged  in  two  opposite  lon- 
gitudinal rows  or  ranks  (orthostichies},\  hence  this  is  called 
a  two-ranked  arrangement. 

(4.)  If,  instead  of  each  new  leaf  forming  at  a  point  half 
of  the  circumference  of  the  punctum  vegetationis  from  the 
last,  it  appears  at  a  point  distant  (always  in  the  same  direc- 
tion) one  third  of  the  circumference,  there  will  be  three  ver- 
tical rows  of  leaves  upon  the  stem ;  this  is  the  three-ranked 
arrangement. 

(5.)  In  rare  cases  the  succeeding  leaf  is  in  each  case  distant 
one  fourth  of  the  circumference  from  the  last,  always  meas- 
uring in  the  same  direction  ;  this  gives  rise  to  the  four- 
ranked  arrangement. 


*  There  are  some  cases  of  false  whorls,  in  which  the  leaves  are  first 
formed  at  different  heights,  and  only  later  by  irregularities  in  the 
growth  of  the  stem  become  whorled. 

f  From  the  Greek  opi?6s,  straight,  and  orfto?,  a  row. 


150  BOTANY. 

(6.)  It  is  very  common  for  the  young  leaves  to  appear  in 
succession  on  the  punctum  vegetationis  at  a  distance  equal 
to  two  fifths  of  the  circumference  from  each,  producing  a 
five-ranked  arrangement. 

(7.)  A  seven-ranked  arrangement  is  rarely  seen;  it  is  pro- 
duced by  the  leaves  following  each  other  at  a  distance  of  two 
sevenths  of  the  circumference. 

(8.)  An  eight-ranked  arrangement,  which  is  a  very  common 
one,  results  from  the  leaves  appearing  at  the  constant  distance 
of  three  eighths  of  the  circumference. 

(9.)  In  like  manner  there  may  be  formed  9,  11,  13,  14,  18, 
21,  23,  29,  34,  37,  47,  55,  and  144  ranks. 

198. — The  distance  between  any  two  succeeding  leaves  is 
called  the  angular  divergence;  it  may  generally  (but  not  always) 
be  deduced  directly  from  the  number  of  ranks  (orthostichies); 
thus  in  the  2-ranked  leaves  it  is  \  ;  in  the  3-ranked,  £  ;  in  4- 
ranked,  \  ;  in  5-ranked,  f  (rarely  -J-) ;  in  7-rauked,  f ;  in  8- 
ranked,  f  (rarely  £);  in  9-ranked,  f ;  in  11-ranked,  -fr ;  in 
13-ranked,  -^  ;  in  14-ranked,  ^ ;  in  18-ranked,  ^  ;  in  21- 
ranked,  2RT ;  in  23-ranked,  -fa ;  in  29-ranked,  ^ ;  in  34- 
ranked,  |f ;  in  37-ranked,  7\  ;  in  47-ranked,  ffi  j  in  55- 
ranked,  f-£  ;  in  144-ranked,  -f/f. 

Examples  of  the  more  common  of  these  arrangements  are  to  be 
found  as  follows  .* 

(a.)  2-ranked  in  Fagus,  Cdtis,  Ulmux,  Vitis,  Tilia,  most  Viciea,  and 
all  grasses. 

(b.)  3-ranked  in  Carex,  Scirpus,  and  most  Jungermannia. 

(c).  4-ranked  in  the  bracts  of  tlie  principal  axis  of  inflorescence  of 
Restio  erectus  and  Thamnochortus  scariosus. 

(d.)  5-ranked  in  Quercus,  Populus,  Robinin,  most  Rosacece,  Borra- 
ginacfOP,  etc. ;  this  is  the  most  common  arrangement  in  Dicotyledons. 

(e.)  7-ranked  in  Melaleuca  ericcefolia,  EupJiorbia  heptagona,  Sedum 
sexangulare,  etc. 

(/.)  8-ranked  in  Polytrichum,  Parietaria  erecta,  Antirrhinum  ma- 
jus,  Raphanus,  Brass'ca,  Hieracinm  piloseUa,  etc. 

(g.)  9-ranked  in  Lycopodium  selago. 

(h.)  11-ranked  not  rarely  in  Sedum  reflexum  and   Opunt 

(k.)  13-ranked  in  Verbascum,  Rhu*  typhina,  Twga  canadensis. 


*  This  list  of  examples  is  from  Hofmeister's  "  Allgemeine  Morphol- 
ogic der  Qewachse,"  p.  448  et  seq. 


ARRANGEMENT  OF  LEA  VES. 


151 


IV 


(I.)  21-ranked   in   the  weak  branches  of  Abies  pectinata   and    Picea 
excelsa,  and  in  most  cones  of  these  species. 

(m.)  34-ranked   on   strong  branches  of  Abies  pectinata  and   Picea 
excelsa,  cones  of  Pinus  larico,  and  the  interfloral 
bracts  of  the  inflorescence  of  Jttidbeckia. 

(n.)  55-ranked  in  tlie  uppermost  shoots  of  many 
piues  and  firs,  in  many  Mdinillaricv,  etc. 

(o.)  144-ranked  in  the  interfloral  bracts  of 
strong-grown  flower-heads  of  HeMu-nthus  annuus. 

199. — By  an  examination  of  various 
leaf-arrangements,  the  following  interest- 
ing but  not  very  important  facts  may  be 
noted  (Fig.  129)  : 

(1.)  If  we  draw  a  line  from  the  inser- 
tion of  one  leaf  to  the  one  next  above  and 
nearest  to  it,  and  continue  this  around  the 
stem  to  the  next,  and  so  on,  a  spiral  will 
be  obtained  agreeing  with  the  order  of 
development  of  the  young  leaves  on  the 
punctum  vegetationis.  To  this  line,  so 
drawn,  the  name  of  Generating  Spiral 
has  been  given. 

(2.)  In  most  cases  the  spiral  passes  more 
than  once  around  the  stem  before  inter- 
secting leaves  of  all  the  ranks. 

(3.)  The  number  of  turns  of  the  spiral 
about  the  stem  in  intersecting  leaves  of 
all  the  ranks  equals  the  numerator  of  the 
fraction  which  indicates  the  angular  di-  mem. 
vergence  of  the  leaves  from  each  other.       and  bottom  in  Roman 

(4.)  Two  sets  of  secondary  spirals  (Par- 
astichies}*  crossing  each  other  at  an  acute 
angle  may  be  observed  on  the  stem  when 
the  leaves  are  close  together,  as  in  Fig.   rranti. 
129  ;   the  leaves  numbered  1,  6,  11,  and  16  form  one  of  the 


*  It  is  of  great  importance  that  the  student  should  not  regard  these 
spirals  (generating  spirals  and  parastichies)  as  anything  more  than 
convenient  means  for  describing  any  particular  leaf-arrangement.  En- 
tirely too  much  attention  has  been  given  to  working  out  all  kinds  of  curi- 
ous mathematical  laws,  which  are,  to  say  the  least,  absolutely  worthless 


152 


BOTANY. 


parastichies  passing  to  the  right,  while  leaves  3,  6,  9,  12. 

15,  18  belong  to  the  parastichies  which  pass  to  the  left. 

(5.)  Upon  counting, 
in  Fig.  129,  it  is  found 
that  there  are  three 
parastichies  passing  to 
the  left  and  five  to  the 
right ;  the  smaller 
number  is  the  same  ad 
the  numerator  of  the 
fraction  expressing  the 
angular  divergence, 
while  the  sum  of  the 
two  equals  the  denomi- 
nator ;  similar  rela- 
tions mav  be  shown  to 

130.  —  Diagram  of   eight-ranked  arrange-         .   ,    .       "  , 
raent; viewed  from  above.  The orthostichieo.  which   8X181  111  Other  CaSCS. 


!  appear  to  be  radial  lines,  are  numbered,  as  in 
Fig.  129,  from  /.  to  VIII  The  leaves  are  number- 
ed from  1  to  16.- After  Sachs. 


200.  —  If  now  we 
study  the  several  ar- 
rangements by  projecting  the  stem  upon  a  flat  surface  in 
such  a  way  that  the  successive 
nodes,  in  ascending  the  stem, 
are  represented  by  smaller 
and  smaller  concentric  circles 
(Fig.  130)  (as  would,  in  fact, 
be  the  case  if  we  made  sections 
through  the  nodes  of  the 
punctum  vegetationis),  it  is 
at  once  evident  that  each  leaf 
is  so  placed  as  to  stand  over 
the  vacant  space  between  the 
previously  formed  ones,  and 
that  as  regards  the  leaves 
formed  after  it,  it  is  equally 
well  situated. 


Hofmeister  formulates  this 


Fig.  130a.— Cross-section  of  a  leaf-bnd 
of  the  Hemlock  Spruce  (Tntga  Canadeit- 
Sis).  Magnified. -After  Hofmeister. 


to  the  morphologist.  So  much  has  this  been  done,  that  the  study  of 
Phyllotaxis  has  in  some  quarters  become  little  more  than  a  species  of 
mathematical  gym  nasties, 


ARRANGEMENT  OF  LEAVES.  153 

as  follows  :*  "New  lateral  members  have  their  origin  above 
the  centre  of  the  widest  gaps  which  are  left  at  the  cir- 
cumference of  the  punctum  vegetationis  between  the  in- 
sertions of  the  nearest  older  members  of  the  same  kind ;" 
and  no  doubt  this  is  one  of  the  most  important  immediate 
causes  which  determine  where  each  new  leaf  is  to  arise.  If  it 
be  asked  why,  then,  are  not  all  leaves  arranged  alike,  the 
answer  must  be  looked  for  in  the  differences  in  structure  of 
the  puncta  vegetationes.  In  cases  where  there  is  an  apical 
cell,  the  arrangement  of  the  leaves  may  be  directly  traced  to 
its  mode  of  division.  In  Phanerogams  it  is  often  clearly  due 


Fig.  1306.— Cross-section  of  the  leaf-bud  of  the  chestnut  (Castaneavesca).  «>,«*, 
the  scale-like  leaves;/"1,/2,./13,  etc.,  the  rudimentary  leave*;  s'-s1.  sa-*2,  etc.,  the 
stipules  belonging  to  the  correspoiulini'ly  numbered  leaves.  Magnified.  —  After 
Hofmeitter. 

to  a  difference  in  the  size  and  form  of  the  punctum  vegeta- 
tionis ;  in  Conifers  and  Composites,  for  example,  it  is  com- 
mon for  a  change  in  the  arrangement  to  take  place  in  pass- 
ing from  the  foliage  leaves  to  the  bracts  of  the  inflorescence 
upon  the  same  stem,  the  number  of  ranks  in  such  cases 
being  greater  on  the  larger  axes.  Doubtless  some  of  the  dif- 
ferences can  be  explained  only  by  taking  into  account,  also, 
the  inherited  peculiarities  of  the  plant. 

*  "  Allgem.  Morphol.,"  p.  482,  and  quoted  in  Sachs' il  Text  Book," 
p.  177. 


154 


BOTANY 


A  study  of  actual  cross-sections  of  leaf-buds  will  make  the 
truth  of  the  previous  statements  more  clearly  evident.    Hof- 


Pig.  130e.— Cross-section  of  a  lateral  bnd  of  the  Virginia  Creeper  (Ami>elop#ia  quin- 
quefolia))  showing  arrangement  of  parts  in  a  double  bud.    Magnified.— After  Hof- 

meister's  figures,*  several  of  which  are  here  reproduced  (Figs. 

130,  «,  to  130,  d),  show 
that  in  all  cases  the  leaf 
rudiments  occupy  in 
the  bud  the  positions  in 
which  they  meet  with 
the  least  resistance. 
This  is  beautifully 
shown  in  the  leaf-bud 
of  the  Hemlock  Spruce 
(Fig.  130,  a).  In  the 
leaf-bud  of  the  chest- 
nut (Fig.  130,  J),  the 
large  stipules  form  the 

F  g.  Iftod.—  Crofs-gection  of  the  leaf-bud  of  a 

youni:  plant  of  Indian  corn  (Zta  mais\.    /.,  the    bud-SCales  :  but  here,  US 
cotyledon,  with  its  two  fibro- vascular  bundles,  1, 1';     .  ' 

II,  III..  IV.,  V.,  the  successive  leaves,  their  mid-    m    the    preceding   Case, 
ribs  marked  by  a  dot.    Magnified.-After  Hofmeis-  L*TI 

ter.  growth  appears  to  follow 

the  "lines  of  least  resistance,"  the  young  leaves  occupying 
the  interspaces  between  the  stipules.   The  double  lateral  bud 


*  In  "  Allgein.  Morphol." 


INTERNAL  STRUCTURE  OF  LEAVES.  155 

of  the  Virginia  Creeper  (Fig.  130,  c)  may  also  be  studied  with 
profit,  and  it  is  curious  to  see  how  the  positions  of  some  of  the 
leaves  are  altered  by  the  fact  that  the  bud  is  a  double  one. 
The  bud  of  the  Indian  corn  (Fig.  130,  d)  shows  that  the  same 
law  holds  in  the  Monocotyledons  as  in  the  Dicotyledons. 

§  V.   THE  INTERNAL  STRUCTURE  OF  LEAVES. 

201. — The  internal  structure  of  leaves  varies  considerably. 
In  all  cases,  however,  the  leaf  is  composed  mainly  of  thin- 
walled,  chlorophyll-bearing  parenchyma,  and  this  is  to  be  re- 
garded as  the  proper  leaf  tissue.  The  fibro-vascular  bundles 
constitute  little  more  than  the  framework  of  the  leaf  and 
its  connection  with  the 
stem,  while  the  epider- 
mis  is  here,  as  elsewhere 
in  the  plant,  a  covering 
tissue.  In  the  related 
members  of  the  plant, 
such  as  bracts,  scales, 
floral  envelopes,  and 
other  phyllome  struc- 
tures, chlorophyll-bear- 
ing parenchyma  is  gen- 
erally wanting,  but 
from  true  leaves  it  is 

rarplvpvpr  nb^fMit      Tlip 

rarely  ever  absent,    i  ic 

Shape    Of     the    leaf,    its  parenchyma  constituting  the  "palisad 

*  ...  _  X,  the  loo*e  and  irregular  parenchyma  of  the  lower 

Size,  position,  and  re-  part  of  the  leaf.  In  a  part  of  the  section  the  chlo- 
,  ,.  ,,  rophyll  granules  are  shown.  x  250.— From  a 

UltlOn     tO    'Other     mem-  drawing  by  J.  C.  Asthur. 

bers,  all  have  somewhat  to  do  with  securing  the  best  disposi- 
tion of  the  essential  leaf  tissue. 

202. — In  leaves  composed  of  one  layer  of  cells,  as  in  many 
mosses  and  some  ferns,  obviously  there  is  no  need  of  any 
special  arrangement  of  the  cells  in  order  to  secure  their  best 
exposure  to  light,  heat,  gases,  etc.  In  thick  leaves,  however, 
the  internal  cells  are  clearly  not  so  well  situated  as  the 
external  ones  are,  hence  we  find  such  leaves  possessing  some 
peculiarities  in  their  structure  which  obviate  this  difficulty. 
Instead  of  being  composed  of  solid  tissues,  their  cells  are 


156 


BOTANY. 


Fig.  132.-Section  of  tne  "  pali- 
***'  tissue  of  the  leaf  of  />«- 


sade 


generally  loosely  arranged,  with  large  intercellular  spaces  be- 
tween them  (Figs.  131  and  133),  and  these  are  in  free  com- 
munication with  the  external  air  by  means  of  the  stomata. 
It  most  frequently  happens  that  this  loose  tissue  is  in  the 
under  part  of  the   leaf,  while  the 
upper  portion  is  composed  of  one  or 
more  layers  of  closely  placed  cells  ; 
and  this  agrees  with  the  general 
distribution  of    the  stomata,  there 
being  usually   many   more    on   the 
under  than  the  upper  surface. 

203. — The  upper  denser  tissue, 
termed  palisade  tissue,  is  composed 
of  elongated  cells,  which  stand  at 
right  angles  to  the  surface  of  the 
leaf  (Fig.  131).  In  cross-section  the 
palisade-cells  are  cylindrical,  with 
small  intercellular  spaces  between 

rom  a  drawing  by  J.  C.  Arthur.    tliem    ^pig.    132),    01'   in    SOHIG  CaSCS 

they  are  more  or  less  compressed  and  angular. 

In  general,  palisade  tissue  is  confined  to  the  upper  surface 
of  the  leaf,  the  lower  being  occu- 
pied by  the  loose  tissue  previously 
mentioned  ;  but  there  are  some  cu- 
rious exceptions  to  this  rule.  The 
most  notable  of  these  is  found  in 
the  leaf  of  Silphium  laciniatum — 
the  so-called  Compass  Plant* — of 
the  Mississippi  Valley  ;  its  chloro- 
phyll-bearing parenchyma  is  almost 
entirely  arranged  as  palisade  tissue, 
so  that  the  upper  and  lower  por- 
tions are  almost  exactly  identical 
in  structure  (Fig.  134).  The  ver-  phy]]  granuleg 
tical  leaves  of  the  Manzanita  of  drawing  by  j.  c.  Arthur, 
the  Pacific  Coast  (Arctostaphylos  pnngens,  var.  platypJiylla] 
have  a  similar  structure. 


*  For  descriptions  of  this  curious  plant,  whose  leaves  have  a  marked 
tendency  to  eland  with  one  edge  to  the  north  and  the  other  to  the 


INTERNAL  STRUCTURE  OF  LEAVES. 


204. — Another  curious  leaf  structure  is  to  be  seen  in 
Stipa  spartea,  the  Porcupine  Grass  of  the  interior  ;  each  long 
harsh  leaf  is  longi- 
tudinally channel- 
led on  its  upper 
surface,  which,  by 
the  twisting  of  the 
basal  portion  of 
the  leaf,  becomes 
apparently  the  low- 
er, and  the  chlo- 
rophyll-bearing pa- 
renchyma is  con- 
fined to  the  sides  of 
the  channels  (Figs. 
135  and  136).  At 
the  bottom  of  each 
channel  the  epider- 
mal cells  are  pe- 
culiarly developed 
into  a  hygroscopic 
tissue,  which,  by 
contracting,  closes 
the  channels  and 
rolls  the  leaf  to- 
gether, as  always 
takes  place  in  dry 


(a)  Many  Monocoty- 
ledons —  as,  for  exam- 
ple, Iris  and  Indian 

corn     afForrl  <rrw>rl  snf» 
corn—  attord  good  spe- 

cimens  of  very  young 

IPIVPQ       Ru  /.nrofnll  ,    "Pl'er  portion  of  th«  leaf;  p\  palisade  tissue  of  th.i 
leaves.     By  carefully    lo»£      £art  of  the  ]eaf  .  .  f/iUS  Been  in  transverse 
removing     the     outer    section.    X  235.  —From  a  drawing  by  the  author. 
leaves  in  succession  all  stages  of  leaf  -development  may  be  obtained. 


Fig.  134.  —  Transverse  section  of  the  leaf  of  Silphvim 
iaci*latum.    ,f  cpjdennis  of  the  upper  surface  ;  «',  epi- 
of  the  lower  surface  ;  p,  palisade  tiscue  of  the 


south—  i.e.,  with  the  leaf-planes  parallel  to  the  plane  of  the  meridian- 
see  articles  in  the  American  Naturalist  :  1870,  p.  495  ;  1871,  p.  1  ; 
1877,  p.  480. 


158 


BOTANY. 


In  tliis  way  often  much  light  will  be  thrown   upon  the  morphology 
of  leaf  parts.* 

(b)  Among  Dicotyledons  it  is  generally  best   to  select  those  whose 
_          „        young  leaves  are  least   downy  or   hairy, 
*          *  *        *         otherwise  the  difficulties  of  the  examina- 

tion are  greatly  increased.  The  lilac  is 
one  of  tbe  liest  for  this  purpose.  Longi- 
tudinal sections,  prepared  as  in  the  ex- 
amination of  young  stems,  should  be 
made. 

(c)  The  young  leaves  in  the  winter  buds 
of  the  hickory  are  instructive,  as  showing 


Fig.  136.  —  A  part  of  a  trans- 
verse section  of  the  1.  af  of  fitipa 
gpartea  in  the  position  it  as- 
sumes —  i.e.,  with  what  is  really 
the  upper  surface  turned  toward 
the  earth.  /,/,  rib*,  each  con 


chlorophyll-bearing  paren 
(figured  dark  in  the  cut), 


(d)  The  study  of  the   arrangement  of 


between  these  are  the  masses  of 
?nchyma 

x  leaves  is  most  interesting  in  the  twigs 
and  cones  of  the  Conifers,  and  the  stems  and  heads  of  the  Composites. 
The  student  should,  however,  before  spending  much  time  in  the 


Fig  136.—  Transverse  section  of  one  of  the  ribs  of  the  leaf  of  fitipa  f/>artfa.    tp, 


chlorophyll-bearing  parenchyma  ;  «,  «,  portions  of  the  epidermic  eoattuniug  stc.in;ita  : 
t  when  the  leaf  rolls  up.    The  blaiik 
ccupied  by  chlorophyll-bearin 

X  125.  —  From  a  drawing  by  the  author. 


,    , 

he,  he,  hygroscopic  cells,  which  contract  when  the  leaf  rolls  up.    The  blaiik  space  on 
the  left  shows  the  extent  of  the  cavity  occupied  by  chlorophyll-bearing  parenchyma. 


examination  of  the  more  difficult  forms,  study  the  twenty-sixth  section 
of  Sachs'   "Text-Book   of   Botany,"   and   the   whole   subject   of  the 

*  In   illustration  of  this,  the  Iris  itself  may  be  cited.     Its  leaf  is 
usually  spoken  of  as  made  by  ihe  folding  of  its  upper  surface  upon 


THE  ROOTS  OF  PLANTS.  159 

arrangement  of  lateral  members  as  given  in  Hofmeister's  "General 
Morphology."  * 

(e)  Tlie  internal  structure  of  the  leaf  may  be  easily  studied.  The 
most  important  sections  are  those  made  at  right  angles  to  the  surface  ; 
but  some  should  be  made  alt-o  parallel  to  it,  so  as  to  show  the  form  of 
the  palisade  cells  and  the  dispositions  of  the  cells  in  the  loose  tissue  of 
the  under  surface.  The  leaves  of  the  lilac,  apple,  cherry,  Tmpatiens, 
Sttphium,  sunflower,  etc.,  are  very  good  for  this  study.  The  more 
difficult  sections  can  be  more  easily  made  after  soaking  the  leaves  for 
some  time  in  strong  alcohol,  thus  hardening  them. 

§  VI.    OF  THE  BOOTS  OF  PLANTS. 

205. — The  root  differs  from  all  other  members  of  the 
plant  in  being  tipped  with  a  peculiar  mass  of  cells — the  Root- 
cap  (pileorhiza  f) — and  in  originating  cndogenously  ;  from 
stems  it  differs  in  never  producing  leaves  or  other  phyllome 
structures.  There  is  some  doubt  as  to  whether  the  Primary 
Root — i.e.,  the  first  root  of  the  embryo — is  not  in  many  cases 
formed  otherwise  than  endogenously  ;  J  but  all  common  roots 
certainly  are  developed  from  beneath  the  surface  of  other 
parts  of  the  plant. 

206.— Roots  may  develop  from  any  part  of  a  plant  which 
contains  fibro-vascular  bundles,  so  that  it  is  no  uncommon 
thing  for  them  to  issue  from  stems  (particularly  their  nodes) 
and  leaves,  as  well  as  from  other  roots.  Whatever  their 
origin,  they  are  essentially  alike,  the  differences,  as  before 
intimated,  being  of  minor  importance.  They  all  agree  in  hav- 

itself,  so  that  the  two  sides  exposed  to  the  air  and  light  are  said  to  be 
in  reality  the  under  surface.  A  study  of  the  very  young  leaf  of  the 
Iris,  along  with  that  of  Hemerocallis,  shows  them  to  be  alike  ;  both  are 
composed  of  an  upper  laterally  flattened  portion  and  a  lower  channelled 
one ;  in  the  Iris  the  upper  portion  grows  fully  as  much  as  the  lower, 
while  in  Heinerocallis  the  growth  is  almost  entirely  confined  to  the  lower 
portion,  the  upper  extending  but  little  and  forming  the  small  extremity 
of  the  leaf.  The  small  tip  of  the  leaf  in  the  latter  case  is  clearly  the 
homologue  of  the  whole  of  the  so-called  ensiform  leaf  of  the  former. 

*  "  Allgemeine  Morphologic  der  Gewachse,"  von  Wilhelm  Hofmeis- 
ter ;  Leipsig,  1868. 

f  From  the  Greek  m'AeoS,  a  cap,  and  frifa,  a  root. 

|  The  mode  of  formation  of  the  Primary  Root  will  be  taken  up  for  each 
group  of  plants  in  Part  II. 


ICO 


BOTANY. 


ing  less  perfectly  developed  tissues  and  tissue  systems.    Their 
epidermal  system  is  more  feebly  developed,  and  they  bear  very 


Fig.  137.— Longitudinal  section  through  the  apex  of  a  root  of  Indian  corn  (Zea 
mate).  All  within  and  above  the  line  •»,  «,  v,  is  the  root  proper,  all  below  and  ontnide 
of  it  is  the  root-cap,  or  ptleorhiza ;  »,  apex  of  root ;  e,  e,  epidermis,  continued  into 
the  dermatogen  at  the  apex  ;  v.  v.  the  thickened  outer  wall  of  the  epidermis  (the 
origin  of  the  root-cap  from  the  dermatogen  is  not  shown  in  this  figure)  ;  sc,  r,  the  cor- 
tex which  if  produced  from  the  pcriblem  at  the  apex  ;  m,  g.f,  the  plerome;  m  be- 
comes the  pith,  g  a  vessel,  f.  wood  ;  a,  a.  outer  and  older  portion  of  the  root-cap  ;  i, 
inner  and  younger  portion 'of  the  root  cap.— After  Sach*. 


THE  ROOTS  OF  PLANTS.  161 

simple  trichomes  —  the  root-hairs.  The  fibro-vascular  bun- 
dles are,  especially  in  the  higher  plants,  of  a  much  lower 
type  than  those  in  the  stems  and  leaves.  The  fundamental 
system  is  also  poorly  developed,  and  has  not  that  variety  of 
tissues  found  in  other  portions  of  the  plant. 

207.  —  Another  remarkable  peculiarity  of  roots  is  that  they 
differ  much  less  from  one  another  in  structure  than  do  their 
steins.    The  young  roots  of  Monocotyledons  have  very  nearly 
the  same  structure  that  those  of  Dicotyledons  have,  and  those 
of  Pteridophytes  do  not  differ  much  from  either.    The  older 
roots  of  Monocotyledons  and  Dicotyledons  differ  considerably, 
on  account  of  changes  in  their  structure  which  take  place 
later,  and  then  each  root  bears  a  closer  resemblance  to  the 
stem  from  which  it  grows,  or  to  which  it  belongs. 

208.  —  The  general  structure  of  the  root-cap  may  be  easily 
understood  from  the  accompanying  figure  (Fig.  137).     It  is 
a  cap-like  mass  of  parenchymatous  cells  which  surrounds 
the  end  of  the  root  ;  its  outer  cells  are  loose,  and  in  some 
cases  are  more  or  less  changed  into  a  mucilaginous  mass; 
in  any  event  they  gradually  lose  their  protoplasm  and  become 
detached  and  destroyed.     The  inner  layers  (i,  s,  Fig.  137)  are 
constantly  developing  from  a  deep-lying  tissue,  the  Dermato- 
gen*  (not  shown  in  the  figure),  so  that  as  the  cap  is  destroyed 
on  the  outside  it  is  renewed  from  the  interior.     By  its  lat- 
eral growth  it  in  some  cases  ensheathes  the  terminal  part  of 
the  root  for  a  considerable  distance. 

209.  —  Back  of  the  root-cap  lies  the  primary  meristem  of 
the  root,  composed,  in  Phanerogams,  of  a  mass  of  small  and 
actively  dividing  cells.     In  this  meristem  there  is  as  yet  no 
differentiation,  but  as  it  is  prolonged  by  rapid  cell-multipli- 
cation the  cells  become  modified  in  its  posterior  portion. 
There  is  thus  a  constantly  advancing  formation  of  meristem, 
followed  at  a  little  distance  by  as  constant  a  modification 
into  other  tissues.     The  usual  course  of  this  differentiation 
is  first  into  a  central  cylindrical  mass,  the  Plerome\  (Fig. 


*  From  the  Greek  dipfia,  SspnaroS,  skin,  and  yswdu,  to  bring  forth  or 
generate. 

f  So  named  by  Hanstein  ("  Scheitelzellegruppe  im  Vegetationspunkt 
der  Phanerogamen,"  1868),  from  the  Greek  7rA?/pu/ia,  a  filling  up. 


162 


BOTANY. 


137,  m,  f,  g),  which  is  ensheathed  by  the  Periblem,*  which 
soon  becomes  transformed  into  the  cortical  portion  of  the 
root  (x,  r,  Fig.  137).  The  epidermis  is  developed  from  the 
region  from  which  the  root-cap  grows,  and,  in  fact,  as  will 
be  shown  below,  it  is  a  continuation  and  modification  of  the 
generating  tissue  of  the  root-cap. 

21O. — In  Fig.  138  the  relation  of  the  parts  is  even  better 
shown  than  in  the  previous  figure.  The  central  plerome 
column  is  surrounded  by  a  layer  of  active  cells,  the  pericam- 


pc 


Fig.  138.—  Median  longitudinal  sectipn  of  the  apex  of  the  root  of  the  buckwheat 
(Fagopijrum  eseulentiim).  pc,  pericambium,  constituting  the  boundary  of  the  plerome 
column  ;  e,  dermatogen  ;  between  e  andpc,  periblem  ;  7t,  root-cap.  —  Alter  De  Bury. 

bium  (pc)  ;  outside  of  the  latter  lies  the  periblem,  or  young 
cortical  portion,  and  still  outside  of  this  the  dermatogen 
(e),  which  further  back  on  the  root  becomes  the  epidermis. 
The  root-cap  (h)  lies  entirely  outside  of,  and  is  quite  distinct 
from,  the  back  portions  of  the  dermatogen,  but  near  the 
apex  of  the  root  there  is  a  tract  in  which  dermatogen  and 
root-cap  apparently  fuse  into  one.  At  this  point  the  layers 

*  Another  of  Hanstein'8  terms,  from  the  Greek  7rep!6?.iyia,  a  cloak. 


THE  ROOTS  OF  PLANTS. 


103 


of  the  root-cap  originate  by  the  successive  divisions  of  the 
dermatogen  cells  by  partitions  parallel  to  the  curved  surface 
of  the  root-tip.  As  the  dermatogen  is  continuous  with  the 
epidermis,  we  may  regard  the  root-cap  as  morphologically 
a  greatly  thickened  and  somewhat  modified  epidermis. 


Fig.  139.— Mode  of  formation  of  the  lateral  roots  in  a  mother-root  of  Trapa  natans. 
A,  a  portionof  the  pericambium  TT,  bounded  externally  by  the  innermost  layer  of  cor- 
tical cells,  r;  d.  dermatogen  ;  n,  the  inner  layer  of  the  pericambium  after  splitting  : 
Ji.  the  same  advanced  somewhat,  the  inner  layer  is  beginning  to  divide;  C,  young 
root  enclosed  in  the  tissue  of  the  mother-root ;  Ji.  r,  cortex  ormother-root ;  IT,  pen- 
cambium  of  mother-root,  from  which  the  new  root  has  been  formed  ;  h,  first  layer  of 
the  root-cap  of  the  new  root,  formed  by  the  splitting  of  its  dermatogen  6  ;  i,  n,  mass 
of  cell-  resulting  from  the  division  of  the  layer  n  in  A  ;  D,  new  root  further  devel- 
oped (the  thick  cortical  tissues  of  the  mother-root  are  not  shown  ;  r,  inner  layer  of 
conical  tissue  of  mother-root) ;  p,  p,  periblem  of  new  root ;  m,  m,  the  tissue  which 
connects  the  new  root  with  the  tissues  of  the  mother-ioot.  Magnified. — After 
Reiiike. 

The  plerome  column  is  a  mass  of  nascent  fibro-vascular 
elements,  and  in  it,  somewhat  further  back  from  the  root-tip, 
a  differentiation  into  the  bundle  takes  place. 


164  BOTANY. 

211. — The  formation  aiid  development  of  a  new  root  is 
interesting  and  suggestive.  It  usually  takes  place  at  some 
distance  from  the  primary  meristem,  in  the  cambium  or  peri- 
cambium.  In  the  root  of  Trapa  natans  it  takes  place  as  fol- 
lows :  The  cells  of  a  restricted  portion  of  the  pericambium 
divide  by  tangential  walls  into  an  outer  layer,  which  becomes 
the  dermatogen  of  the  new  root  (d,  Fig.  139),  and  an  inner 
layer,  from  which  develops,  its  primary  meristem  (n,  Fig. 
139).  The  inner  cells  multiply  by  divisions  in  several  direc- 
tions, and  as  their  mass  increases  they  push  out  the  young 
dermatogen  (B,  C,  and  D,  Fig.  139).  From  the  dermato- 
gen the  first  layer  of  the  root-cap  is  formed  by  the  tangen- 
tial division  of  its  cells  (C,  h,  Fig.  139).  These  growing 
tissues  push  out  the  overlying  portions  of  the  mother-root, 
and  finally  break  through  them.  The  root  is  thus  seen  to 
be  a  strictly  endogenous  formation  ;  there  is  no  connection 
between  its  tissues  and  the  epidermal  and  cortical  portions 
of  the  mother-root,  the  sole  connection  being  with  the  deep- 
lying  tissues  in,  or  in  connection  with,  the  fibro-vascular 
bundles.  Herein  roots  present  a  marked  contrast  to  stems 
and  leaves,  which,  as  a  rule,  develop  from  the  exterior  of 
the  plant-body,  or,  in  other  words,  are  exogenous  in  their 
origin. 

212. — Roots  are  rarely  arranged  in  as  regular  an  order  as 
are  stems.  In  general  they  arise  in  acropetal  order  upon  the 
mother-roots  of  Pteridophytes  and  the  primary  roots  of  Pha- 
nerogams, but  this  order  is  subject  to  many  more  disturbing 
influences  than  in  the  case  of  the  origin  of  stems.  As  to 
position,  they  may  arise  in  rows  or  ranks,  or  in  particular 
spots,  dependent  upon  the  disposition  of  the  fibro-vascular 
bundles,  or  the  generating  tissues  in  the  root  or  stem.  Thus 
it  may  happen  that  on  a  root  or  stem  there  may  be  as  many 
rows  of  roots  as  there  are  fibro-vascular  bundles.  Roots 
which  develop  from  stems  are  generally  much  more  affected 
by  external  influences  than  those  which  grow  from  other 
roots.  The  degree  of  moisture  of  the  different  parts  of  the 
stem  appears  to  have  much  to  do  in  determining  the  point 
of  the  appearance  of  roots  ;  this  is  seen  in  stems  which  touch 
the  ground,  as  in  the  tomato,  and  in  climbing  plants.  MS  tin- 


THE  ROOTS  OF  PLANTS.  165 

Ivy  (Hedera),  Poison  Ivy  (Rhus),  the  Virginia  Creeper  (Am- 
pelopsis),  etc. 

213. — In  form  roots  are  generally  fibrous,  and  this  is 
manifestly  their  best  form,  in  so  far  as  they  are  organs  for 
obtaining  dissolved  matters  from  the  soil.  In  perennials, 
however,  as  the  stems  become  larger  the  roots  increase  cor- 
respondingly to  support  the  additional  weight ;  they  thus 
become  hold-fasts  or  mechanical  supports.  In  other  cases 
they  are  made  the  recipients  of  assimilated  matters,  as  starch, 
sugar,  etc.,  and  thus  become  thickened  storehouses. 

In  many  cases  the  latter  are  capable  of  forming  buds  and 
of  sending  out  new  stems  from  the  ineristem  tissue  in,  or  in 
the  vicinity  of,  the  fibre-vascular  bundles,  as  is  notably  the 
case  in  the  tuberous  root  of  the  SAveet  potato. 

(a)  The  root-cap  may  be  studied  with  the  least  difficulty  in  roots 
which  are  grown  in  water.     Those  of  Lemna  may  be  easily  obtained, 
and  are  excellent. 

(b)  Roots  of   Indian   corn,   Hyacinth,  Impatiens,  etc.,  also  furnish 
easily  made  and  good  specimens. 

(e)  In  preparing  specimens  for  examination  thin  longitudinal  sections 
should  be  made,  and  these  should  be  supplemented  by  transverse  sec- 
tions taken  at  various  heights  on  a  root-tip. 

(d)  By  the  use  of  staining  fluids,  as  carmine,  magenta,  etc.,  some 
points  in  the  structure  will  be  made  more  evident.     Iodine  should  also 
be  used  ;  by  treatment  with  it,  the  starch  which  is  present  in  the  root- 
tip  in  many,  if  not  all,  cases  may  be  seen. 

(e)  For  studying  the  formation  and  development  of  new  roots  suc- 
culent plants  should  be  chosen,  as  the  sections  of  their  tissues  are  more 
transparent  than  those  of  other  plants.     On  this  account  many  water 
plants  are  to  be  preferred.     Anion<j  land   plants,   Impatiens  is  one  of 
the  bust;  it  always  has  a  large  number  of  forming  roots  on  its  stem 
near  or  at  the  surface  of  the  ground. 

(f)  Vertical  sections  of  the  papillae,  showing  the  point  of  appearance 
of  new   roots,  should  be  made.     If  many  longitudinal  slices  of  the 
lower  part  of  the  stem  of  Impatiens  are  made  in  a  section-cutter,  it  will 
almost  certainly  happen  that  some  good  specimens  will  be  found. 


CHAPTER    X. 

THE  CONSTITUENTS  OF  PLANTS. 

§  I.  THE  WATER  IN  THE  PLANT. 

214.— Amount  of  Water  in  Plants.  All  living  parts  of 
plants  are  abundantly  supplied  with  water.  It  is  always 
present  in  living  protoplasm,  and  the  greater  its  activity  the 
more  watery  is  its  composition.  The  cell-walls  of  living 
tissues  also  contain  large  quantities  of  water ;  and  in  plants 
composed  of  many  cells  (as  the  larger  flowering  plants)  even 
those  cells  and  tissues  which  have  lost  their  activity  generally 
have  their  walls  saturated  with  water.  In  ordinary  herbace- 
ous land  plants  the  amount  of  water  is  not  far  from  75  per 
cent  of  their  whole  weight ;  thus  in  growing  rye  it  is  about 
73  per  cent ;  in  meadow  grass,  before  bjossoming,  75 — after 
blossoming,  69  ;  in  lucerne,  when  young,  81 — in  blossom,  74 ; 
in  white  clover,  80 ;  in  red  clover,  before  blossoming,  83 — 
after  blossoming,  78  ;  in  oats,  in  blossom,  81 ;  in  Indian 
corn,  in  blossom,  84.  In  certain  parts  of  plants  the  per- 
centage is  still  higher  ;  for  example,  in  the  leaves  of  the  field 
beet  it  is  90  ;  in  tubers  of  the  potato,  75  ;  in  the  thickened 
root  of  the  parsnip,  88 ;  in  the  similar  root  of  the  turnip, 
92.  In  aquatic  plants  the  percentage  is  much  higher,  often 
exceeding  95 ;  it  is  so  abundant  in  many  of  the  simpler 
forma  that  upon  drying  nothing  but  an  exceedingly  thin  and 
delicate  film  is  left. 

215.— Water  in  the  Protoplasm.  As  explained  in  para- 
graphs 4  and  5  (page  5),  living  protoplasm  has  the  power 
of  imbibing  water,  and  thereby  of  increasing  its  fluidity. 
Even  after  it  has  imbibed  all  the  water  which  it  can  retain 
it  continues  the  process,  and  separates  the  surplus  in  drops 


THE   WATER  IN  THE  PLANT.  167 

in  its  interior,  the  so-called  vacuoles.  Now  an  examination 
of  the  cells  of  rapidly  growing  tissues  shows  that  their  pro- 
toplasm is  much  more  watery  than  that  of  living,  but  dor- 
mant tissues — e.g.,  those  of  seeds — and  one  of  the  first  signs 
of  activity  in  the  latter  is  the  imbibition  of  water. 

This  avidity  of  protoplasm  for  water  plays  an  important 
part  in  the  general  economy  of  the  plant.  By  it  all  the  cells 
which  contain  protoplasm  are  kept  turgid,  and  by  the  ten- 
sion thus  created  the  soft  parts  of  plants  are  made  rigid. 
It  plays  no  small  part  also  in  keeping  up  the  supply  of 
moisture  in  living  tissues  when  wasted  by  evaporation.  (See 
paragraph  220  et  seq.) 

216.— Water  in  the  Cell- walls.  In  the  cell- walls,  accord- 
ing to  Nageli's  theory,  the  water  forms  thinner  or  thicker 
layers  surrounding  the  crystalline  molecules  of  cellulose.  (See 
paragraph  37,  p.  32.)  The  wall  of  the  cell  is  thus  not  a 
membrane  which  separates  the  water  of  one  cell  cavity  from 
that  in  the  next,  but  rather  a  pervious  stratum,  composed  of 
solid  particles  which  are  not  in  contact,  and  between  which 
the  water  freely  passes.  In  a  living  tissue  the  water  is  con- 
tinuous from  cell  to  cell,  and  constantly  tends  to  be  in  equi- 
librium— i.e.,  the  turgidity  of  the  cells  is  approximately 
equal  throughout  the  tissue,  and  likewise  the  wateriness  of 
both  cell-walls  and  cell-contents. 

In  the  simpler  aquatic  plants  the  water  of  the  cells  and 
their  walls  is  continuous  with  that  in  which  they  grow. 
Likewise  the  water  in  the  tissues  of  roots  or  other  absorbing 
organs  of  the  higher  aquatic  plants  is  continuous  with  that 
which  surrounds  them;  and  even  in  ordinary  terrestrial  plants 
there  is  a  perfect  continuity  of  the  water  in  the  root  tissues 
with  the  moisture  of  the  soil. 

217. -Water  in  Intercellular  Spaces.  In  some  cases  the 
intercellular  spaces  and  passages,  and  even  the  vessels  of  the 
more  succulent  plants,  are  filled  with  water,  thus  increasing 
its  amount  in  the  whole  plant  very  considerably.  More 
commonly,  however,  these  cavities  are  filled  with  air  and 
gases,  the  vessels  having  curly  lost  the  protoplasm  which 
they  contained  at  first.  It  is  probable,  moreover,  that  the 


168  BOTANY. 

water  which  is  occasionally  found  in  their  cavities  has  little 
or  no  physiological  relation. 

2 1 8.— The  Equilibrium  of  the  Water  in  the  Plant.  The 
water  in  the  tissues  of  every  plant  tends  constantly  to  become 
in  equilibrium,  and  this  state  would  soon  be  reached  were  it 
not  for  certain  disturbing  causes  which  are  almost  as  con- 
stantly in  action.  In  any  cell  an  equilibrium  may  soon  be 
reached  between  the  two  forces  which  reside  respectively  in 
the  cell-wall  and  the  protoplasm,  viz.,  (1)  the  attraction  of 
the  surfaces  of  the  molecules  for  the  water,  and  (2)  the 
"imbibition  power"  of  protoplasm.  This  equilibrium  once 
attained,  all  motion  of  the  water  must  cease,  and  it  must 
remain  at  rest  until  disturbed  by  some  other  force  or  forces. 
This  condition,  or  one  approximating  very  closely  to  it,  is 
reached  by  many  of  the  perennial  plants  during  the  winter 
or  period  of  rest. 

219.— Disturbance  of  Equilibrium.  During  the  growing 
stages  of  plants  the  equilibrium  of  the  water  is  constantly 
disturbed  in  one  or  more  ways,  viz.,  (1)  by  the  chemical 
processes  within  the  cells  ;  (2)  by  the  "  imbibition  power"  of 
the  protoplasm  and  walls  of  newly  formed  cells  ;  (3)  by  the 
evaporation  of  a  portion  of  the  water. 

The  chemical  processes  within  the  cell  include  :  (1)  the 
actual  use  of  water  by  breaking  it  up  into  hydrogen  and 
oxygen ;  every  molecule  which  is  so  broken  up  leaves  a 
vacancy  which,  sooner  or  later,  must  be  replaced  ;  (2)  the 
formation  of  substances  which  are  more  soluble  than  those 
from  which  they  were  formed ;  (3)  the  formation  of  sub- 
stances which  are  less  soluble  than  those  from  which  they 
were  formed.  These  processes  take  place  in  all  cells,  even 
those  of  the  simplest  plants. 

In  plants  composed  of  tissues,  wherever  new  cells  are 
forming  and  developing,  the  new  protoplasm  and  cell-walls 
require  considerable  quantities  of  water  to  satisfy  their 
molecular  attraction  (paragraphs  215  and  216  above)  ;  this 
supply  is  always  made  in  part  or  entirely  at  the  expense 
of  the  adjacent  cells.  In  many  aquatic  plants  there  can 
be  little  doubt  that  the  needed  water  in  meristem  tissues 
is  obtained  partly  by  direct  absorption  from  the  surround- 


THE   WATER  IN   THE  PLANT.  169 

ing  water,  but  this  can  only  be  the  case  with  the  external 
cells  ;  the  deep-lying  ones  must  obtain  their  supply  from  the 
cells  which  surround  them.  In  aerial  parts  of  plants  the 
newly  formed  cells  obtain  all  their  water  from  the  adjacent 
cells. 

220.— Evaporation  of  Water.  In  the  aerial  parts  of  plants 
the  evaporation  of  water  from  their  surfaces  is  a  far  more 
powerful  disturbing  cause  than  either  of  the  two  preceding. 
Whenever  a  cell  is  exposed  to  dry  air  at  ordinary  tempera- 
tures a  portion  of  its  water  passes  off  by  evaporation  ;  this 
immediately  disturbs  the  equilibrium  of  water  throughout 
the  tissue,  and  the  more  rapid  or  the  longer  continued  the 
evaporation,  the  greater  the  disturbance. 

Evaporation  (called  also  transpiration  and  exhalation) 
from  living  cells  or  tissues  is  dependent  upon  a  number  of 
conditions,  some  of  which  are  entirely  exterior,  while  others 
are  connected  with  the  structure  of  the  plant  itself.  Among 
the  former,  the  most  important  is  the  condition  of  the  air  as 
to  the  amount  of  moisture  which  it  contains.  In  air  satu- 
rated with  moisture  no  evaporation  can  take  place  ;*  but 
whenever  the  amount  of  moisture  falls  below  the  point  of 
saturation,  if  the  other  conditions  are  favorable,  evaporation 
takes  place.  The  temperature  of  the  air  (and,  as  a  conse- 
quence, that  of  the  plant  also)  has  some  effect  upon  the 
rapidity  of  evaporation.  It  appears  that  there  is  an  increase 
in  the  amount  of  water  given  off  as  the  temperature  rises ; 
this  may  be  due,  however,  to  the  fact  that  with  such  increase 
of  the  temperature  of  the  air  there  is  generally  a  considerable 
decrease  in  its  moisture.  The  direct  influence  of  light  upon 
evaporation  is  also  somewhat  doubtful.  While  there  can  be 
no  doubt  that  plants  generally  lose  more  water  in  the  light 
than  in  darkness,  it  may  be  questioned  whether  this  is  not 


*  Many  experiments,  at  first  sight,  seem  to  show  that  plants  evapo- 
rate water  in  air  saturated  with  moisture  ;  but  Knop  has  found 
("  Versuchs-Stationen,"  Vol.  VI.,  p.  255)  that,  under  similar  conditions, 
moist  pieces  of  paper  or  wood  also  evaporate  water,  thus  showing  that 
the  air,  instead  of  being  saturated,  lacked  somewhat  of  being  so. 


170  BOTANY. 

mainly  due  to  the  increased  heat  and  dryness  which  are 
common  accompaniments  of  the  increase  of  light.* 

221. — In  enumerating  the  internal  conditions  one  general 
one  must  not  be  forgotten,  which  is,  that  the  water  in  plant- 
cells  contains  many  substances  in  solution,  and  consequently 
evaporates  less  rapidly  than  pure  water,  in  accordance  with 
well-known  physical  laws.  Moreover,  the  attraction  of  the 
molecules  of  the  cell-walls  for  the  water  layers  counteracts, 
to  a  considerable  extent,  the  tendency  to  evaporation  ;  and 
in  the  same  manner,  even  to  a  greater  extent,  the  water  is 
prevented  from  passing  off  By  the  "imbibition  power  "of 
protoplasm.  It  is,  in  fact,  impossible  to  deprive  cellulose 
and  protoplasm  of  their  intermolecular  water  in  dry  air  at 
ordinary  temperatures. 

In  all  the  aerial  parts  of  higher  plants  the  epidermis 
offers  more  or  less  resistance  to  the  escape  of  the  water  of  the 
underlying  tissues.  This  is  mainly  accomplished  by  the 
thick  and  cuticularized  outer  wall  of  the  epidermal  layer  ;  in 
many  cases,  especially  in  plants  growing  naturally  in  very 
dry  regions,  the  epidermis  consists  of  several  layers  of  cells, 
which  offer  still  more  resistance  to  evaporation  by  being 
themselves  filled  with  moist  air  only.  Among  the  lower 
plants,  the  single  reproductive  cells  (spores)  are  guarded 
against  the  loss  of  water  by  having  their  walls  greatly  thick- 
ened and  cuticularized.  Even  in  the  lowest  plants,  the  Slime 
Moulds  (Myxomycetes),  the  naked  masses  of  protoplasm, 
when  placed  in  dry  air,  will  contract  into  rounded  masses, 
which  then  become  covered  with  a  somewhat  impervious 
envelope  (paragraph  23,  c  :  page  21). 

222. — The  stomata  of  the  green  and  succulent  parts  of 
higher  plants  control  to  a  great  extent  the  amount  and 
rapidity  of  their  exhalation.  In  leaves,  for  example,  where, 
on  account  of  its  cuticularization,  there  can  be  but  little 
evaporation  through  the  epidermis,  it  is  dependent  upon  the 

*  I  am  aware  that  some  experiments  made  with  plants  in  saturated 
and  in  dry  air  appear  to  show  that  in  direct  sunlight  there  is  a  rapid 
evaporation.  I  cannot,  however,  regard  these  experiments  as  con. 
elusive. 


THE  WATER  IN  THE  PLANT.  171 

number,  size,  and  condition  (i.e.,  whether  open  or  closed) 
of  the  stomata.  As  previously  described  (paragraph  1 30,  p. 
99),  the  stomata  are  placed  over  intercellular  spaces,  which 
are  in  communication  with  the  intercellular  passages  of  the 
plant.  These  spaces  and  passages  are  filled  with  moist  air 
and  gases,  which,  when  the  stomata  are  open,  expand  and 
contract  with  every  change  of  temperature  or  atmospheric 
pressure,  and  thus  permit  the  escape  of  considerable  amounts 
of  water  ;  when,  on  the  other  hand,  the  stomata  are  closed, 
little  or  no  escape  of  moisture  is  possible.  The  opening  and 
closing  of  the  stomata  appear  to  depend  upon  the  amount  of 
light ;  they  open  more  widely  the  greater  the  amount  of 
light,  and  close  almost  completely  in  darkness.  The  amount 
of  moisture  on  the  surface  of  the  epidermis  appears  also  to 
affect  somewhat  the  opening  and  closing  of  the  stomata  ; 
when  the  epidermis  is  very  dry  the  stomata  are  generally 
closed,  and  vice  versa. 

223.— The  Amount  of  Evaporation.  The  conditions  con- 
trolling evaporation  are  thus  seen  to  be  many  and  various. 
They  never,  or  but  very  rarely,  act  singly,  two  or  more  of 
them  usually  acting  together  with  varying  intensity,  so  that 
the  problem  of  the  amount  of  evaporation  taking  place  at 
any  particular  time  is  a  complex  and  difficult  one.  All  the 
observations  yet  made,  and  which  have  necessarily  been  upon 
a  very  small  scale,  indicate  that  the  rate  of  evaporation  is 
actually  very  slow.  Thus  Hales  long  ago  found  that  the 
amount  of  water  evaporated  from  a  vine  in  twelve  hours  of 
daylight  equalled  a  film  only  .13  mm.  (.005  in.)  thick,  and 
having  an  extent  as  great  as  that  of  the  evaporating  surface  ; 
the  amount  from  a  cabbage  in  the  same  time  equalled  a  film 
.31  mm.  (.012  in.)  thick  ;  from  an  apple  tree,  .25  mm.  (.01 
in.)  thick  ;  from  a  sunflower  in  a  day  and  a  night,  equal  to 
a  film  .15  mm.  (.006  in.)  thick.*  Mflller  found  the  rate  of 
evaporation  from  the  leaves  of  Hcemantkus  puniceus  to  be 
only  one  seventeenth  as  rapid  as  that  from  an  equal  area  of 
water  during  the  same  time.  Sachs  found  the  evaporation 

*  "  Statical  Essays  :  Vegetable  Statics,"  by  Stephen  Hales.  1727. 
Fourth  edition.  1769.  p.  21. 


172  BOTANY. 

from  the  leaves  of  the  White  Poplar  to  be  about  one  third  as 
rapid  as  from  water,  linger  places  the  evaporation  from 
most  leaves  at  about  one  third  that  from  equal  areas  of 
water ;  in  some  cases,  however,  running  as  low  as  one  fifth 
and  one  sixth.  * 

224.  — Pfaff  calculated  the  amount  of  water  evaporated 
from  an  isolated  oak  tree  during  the  growing  season.     The 
tree  selected  was  a  close-topped  one  6f  metres  (20  ft.)  high, 
bearing  about  700,000  leaves.     The  results  were  as  follows  : 
May  (14  days) 883  kilograms  =  (  1,944  Ibs.) 


June 26,023 

July 28,757 

August 21,745 

September 17,674 


=  (57,250  " 
=  (63,265  " 
=  (47,839  " 


=  (37,450 


October 17,023 

The  evaporation  from  each  leaf  was  for  the  season  of  five 
and  a  half  months  (one  hundred  and  sixty-seven  days)  .16 
kilograms  (.35  Ibs.) ;  allowing  forty-eight  square  centimetres 
of  surface  to  each  leaf,  this  amounted  to  a  layer  of  water 
3.33  centimetres  (1.31  in.)  deep  over  the  whole  evaporating 
surface,  f 

225.— The  Movement  of  Water  in  the  Plant.  It  is  clear, 
from  what  has  been  said,  that  in  polycellular  plants  there 
must  be  a  considerable  movement  of  water  in  some  parts,  to 
supply  the  loss  by  evaporation.  Thus  in  trees  there  must  be 
a  movement  of  water  through  the  roots,  stems,  and  branches 
to  the  leaves,  to  replace  the  loss  in  the  latter.  This  is  so 
evident  that  it  scarcely  needs  demonstration  ;  it  can,  how- 
ever, be  shown  by  cutting  off  a  leafy  shoot  at  a  time  when 

*  The  three  last  statements  and  the  following  are  given  on  the 
authority  of  Duchartre  ("  Elements  de  Botanique,"  second  edition,  1877, 
pp.  844  and  846). 

f  Pfaff  found  that  the  water  evaporated  during  the  season,  when  con- 
sidered with  reference  to  the  area  of  ground  covered  by  the  tree  top, 
was  equal  to  a  layer  5.39  metres  high  (212  inches).  Observation  had 
shown  the  annual  rain-fall  to  be  .65  metres  (25.6  inches) ;  so  that  the 
water  evaporated  from  the  tree  was  eight  times  the  amount  which  fell 
upon  the  earth  under  it.  The  evaporation  is  very  much  less  in  dense 
forests  than  in  isolated  trees,  but  with  every  allowance  it  is  sufficient 
in  dry,  hot  seasons  to  quickly  exhaust  the  moisture  of  the  soil. 


THE  WATER  IN  THE  PLANT.  173 

evaporation  is  rapid  ;  in  a  short  time  the  leaves  wither  and 
become  dried  up,  unless  the  cut  portion  of  the  shoot  be 
placed  in  a  vessel  of  water  ;  in  the  latter  case  the  water  will 
pass  rapidly  into  the  shoot,  and  the  leaves  will  retain  their 
normal  condition.  If  in  such  an  experiment  a  colored  watery 
solution  (as  of  the  juice  of  Poke  berries)  be  used  instead  of 
pure  water,  it  will  be  seen  that  the  liquid  has  passed  more 
abundantly  through  certain  tracts  than  through  others,  in- 
dicating that  the  tissues  are  not  equally  good  as  conductors 
of  watery  solutions.  As  would  readily  be  surmised,  the 
tissues  in  ordinary  plants  which  appear  to  be  the  best  con- 
ductors are  those  composed  of  elongated  wood-cells,  and  it  is 
doubtless  through  them  that  the  greater  part  of  the  water 
passes.  Furthermore,  it  is  probable  that  the  movement  of 
the  water  is  through  the  substance  of  the  cell-walls,  and  not, 
at  least  to  any  great  extent,  through  the  cell  cavities.  Ac- 
cording to  this  view,  the  force  which  raises  the  water,  in 
some  cases  to  the  height  of  a  hundred  metres  or  more,  is  the 
attraction  of  the  surfaces  of  the  crystal  molecules  for  the 
layers  of  water  which  surround  them. 

226. — The  rapidity  of  the  upward  movement  of  water  evi- 
dently varies  directly  as  the  rapidity  of  evaporation,  and  in- 
versely as  the  area  of  the  conducting  tissue  in  transverse  sec- 
tion. As  both  these  factors  are  variable,  it  is  impossible  to 
give  an  average  rate  of  movement.  Sachs  estimated  the 
rate  of  ascent  in  a  branch  of  the  Silver  Poplar,  from  which 
there  was  strong  evaporation,  at  23  cm.  (9  in.)  per  hour. 
McNab,  by  watering  plants  with  a  solution  of  lithium  citrate 
and  then  examining  the  ashes  at  successive  points,  found  the 
rate  in  a  Cherry  Laurel  to  be  101  cm.  (40  in.)  per  hour.  Pfit- 
zer  obtained  the  astonishing  result  of  22  metres  (72  ft.)  per 
hour  in  the  Sunflower  ;  there  is  but  little  doubt,  however, 
that  this  is  entirely  too  high. 

(a)  In  addition  to  the  movements  of  the  water  described  above,  that 
which  has  been  called  root  pressure  requires  a  brief  mention.  If  the 
root  of  a  vigorously  growing  plant  be  cut  off  near  the  surface  of  the 
ground  and  a  glass  tube  attached  toils  upper  end,  the  water  of  the  root 
will  be  forced  out,  often  to  a  considerable  height.  Hales*  noted  a  pressure 

*  Statical  Essays,  p.  114. 


174  BOTANY. 

upon  a  mercurial  gauge  equal  to  11  metres  (36.5  ft.)  of  water  when  at- 
tached to  the  root  of  a  vine  (  Vitis).  Clark,*  in  a  similar  manner,  found 
the  pressure  from  a  root  of  the  birch  (Betuln  lutea)  to  be  equal  to  25.8 
metres  (84.7  ft.)  of  water.  This  root  pressure  appears  to  be  greatest 
when  the  evaporation  from  the  leaves  is  leust  ;  in  fact,  if  the  experi- 
ment is  made  while  transpiration  is  very  active,  there  is  always  for  a 
while  a  considerable  absorption  of  water  by  the  cut  end  of  the  root, 
due  probably  to  the  fact  that  the  cell-walls  had  been  to  a  certain  ex- 
tent robbed  of  their  water  by  the  evaporation  from  above.  Root  pres- 
sure is  probably  a  purely  physical  phenomenon,  due  to  a  kind  of  en- 
dosmotic  action  taking  place  in  the  root  cells. 

(6)  The  flow  of  water  (sap)  from  the  stems  and  branches  of  certain 
trees,  notably  from  the  Sugar  Maple,  appears  to  be  due  to  the  quick 
alternate  expansion  and  contraction  of  the  air  and  other  gases  in  the 
tissues  from  the  quick  changes  of  temperature.  The  water  is  forced  out 
of  openings  in  the  stem  when  the  temperature  suddenly  rises  ;  when 
the  temperature  suddenly  falls,  as  at  night,  there  is  a  suction  of  water 
or  air  into  the  stem.  When  the  temperature  is  nearly  uniform,  whether 
in  winter  or  summer,  there  is  no  flow  of  sap. 

§  II.  As  TO  SOLUTIONS. 

227. — The  water  in  the  plant  holds  in  solution  several 
substances,  so  that  it  is  not  water  alone,  but  in  reality  a 
complex  solution.  Some  of  the  substances  in  solution  are 
solids,  as  the  inorganic  salts  taken  up  from  the  soil  or  water, 
while  others  are  gaseous,  as  the  air  and  carbon  dioxide  taken 
up  in  the  water  by  the  roots,  or  absorbed  by  the  leaves  and 
there  entering  into  solution  in  the  water.  The  final  use  of 
these  solutions  will  be  spoken  of  further  on  ;  here  it  is  only 
necessary  to  point  out  some  of  the  more  important  general 
facts  as  to  solution  and  diffusion  : 

1st.  When  a  substance  has  entered  into  solution  it  still 
exists  as  that  substance,  and  the  water  in  which  it  is  dis- 
solved is  in  one  sense  pure.  This  is  readily  shown  by  driving 
off  the  water  by  heat,  when  the  dissolved  substance  is  .iirain 
obtained  in  its  original  solid  state. 

2d.  As  soon  as  solution  begins  the  process  of  diffusion 

*  In  1873,  recorded  in  the  Twenty-first  Report  of  the  Secretary  of 
the  Massachusetts  State  Board  of  Agriculture.  See  also  further  re- 
sults by  the  same  observer  in  the  Twenty-second  Report. 


PLANT  FOOD,  175 

necessarily  commences  also  ;  this  is  the  passage  of  the  mole- 
cules of  the  dissolved  substance  through  the  water  without  a 
movement  of  the  latter.  Thus  in  perfectly  quiescent  water 
a  substance  may  diffuse  itself  between  the  molecules  of  the 
latter  to  considerable  distances,  and  this  may  take  place  in 
any  direction,  even  when  the  substance  is  heavier  than  water  ; 
thus  common  salt  placed  in  the  bottom  of  a  tall  vessel  of 
water  will  dissolve  and  gradually  diffuse  throughout  the 
whole. 

3d.  The  rapidity  of  diffusion  varies  for  different  sub- 
stances ;  thus  the  diffusion  rate  of  sugar  is  more  than  three 
times  that  of  common  salt  (exactly  as  365  to  116). 

4th.  Two  or  more  diffusions  may  take  place  at  the  same 
time  in  the  same  fluid,  and  they  may  move  in  the  same  or  in 
opposite  directions. 

5th.  Diffusion  continues  until  all  parts  of  the  solution 
contain  equal  quantities  of  the  dissolved  substance. 

6th.  If  at  any  point  in  a  solution  the  dissolved  substance 
be  removed  in  some  way,  as,  for  example,  by  the  formation 
of  a  new  salt  by  chemical  reaction,  there  will  be,  as  a  conse- 
quence, a  continued  diffusion  toward  that  point ;  and  if  the 
new  salt  be  a  soluble  one  it  must  diffuse  in  every  direction 
from  the  point  of  its  formation.  Thus  the  molecular  move- 
ments may  become  quite  complex. 


§  III.  PLANT  FOOD. 

228.— The  most  important  elements  which  are  used  in 
the  nutrition  of  plants,  or  which,  in  other  words,  enter  into 
their  food,  are  Carbon,  Hydrogen,  Oxygen,  Nitrogen,  Sul- 
phur, Iron,  and  Potassium.  These  all  appear  to  be  necessary 
to  the  life  and  growth  of  the  plant,  and  if  any  of  them  are 
wanting  in  the  water,  soil,  or  air  from  which  the  plant  de- 
rives its  nourishment,  death  from  starvation  will  soon  follow. 
There  are  other  elements  which  are  made  use  of  by  plants, 
but  as  life  may  be  prolonged  without  them,  they  are  regarded 
as  of  secondary  importance.  In  this  list  are  Phosphorus, 
Calcium,  Sodium,  Magnesium,  Chlorine,  and  Silicon, 


176  BOTANY. 

229.— The  Compounds  Used.  With  the  single  exception 
of  oxygen,  the  elementary  constituents  named  above  do 
not  enter  into  the  food  of  plants  in  an  uncombined  state  ; 
on  the  contrary,  they  are  always  absorbed  in  the  condition 
of  compounds,  as  water,  carbon  dioxide,  and  the 

Nitrates        ]  ( Ammonia. 

Sulphates      |          |  Potash. 

Carbonates  !  f  I  Lime. 
Phosphates  f  1  Iron. 
Silicates,  or  j  Soda,  or 

Chlorides     J  [  Magnesia. 

In  addition  to  these,  many  organic  compounds  are  ab- 
sorbed in  particular  cases,  as  in  those  plants  which  live  in 
decaying  animal  or  vegetable  matter  (saprophytes),  as  well 
as  those  which  absorb  the  juices  from  living  plants  (para- 
sites). 

230. — How  the  Pood  is  Obtained.— In  the  case  of  aquatic 
plants,  these  compounds  are  taken  into  the  plant-body  by  a 
process  of  diffusion  from  the  surrounding  water  ;  in  terres- 
trial plants  the  gaseous  compounds,  as  carbon  dioxide  and 
carbonate  of  ammonia,  are  absorbed — at  least  in  part — by  the 
leaves  directly  from  the  surrounding  air,  while  the  solutions 
of  these  and  the  other  compounds  in  the  water  in  the  soil 
find  their  way  into  the  plant  by  diffusion. 

23Oa.— How  the  Pood  is  Transported  in  the  Plant. 
Once  within  the  plant-body,  the  food  materials  diffuse  to  all 
watery  parts,  in  the  case  of  the  larger  terrestrial  plants  ris- 
ing through  the  stem  to  the  leaves.  By  diffusion,  there  is  a 
constant  tendency  toward  an  equal  distribution  throughout 
the  plant  of  the  solutions  which  enter  it,  and  if  there  were 
no  disturbing  chemical  reactions  taking  place,  such  a  condi- 
tion would  in  most  plants  be  soon  reached.  It  is  quite 
probable,  indeed,  that  this  actually  happens  for  certain  sub- 
stances which  are  found  in  solution  in  the  soil  or  water,  and 
which,  entering  plants,  diffuse  through  them  to  all  parts, 
but  not  being  used  they  soon  reach  a  state  of  equal  diffusion, 
which  is  only  slightly  disturbed  by  the  extension  of  the 
plant-body  by  growth.  Doubtless  the  rapid  diffusion  of 
food  materials  throughout  terrestrial  plants  is  aided  by  the 


PLANT  FOOD.  177 

evaporation  of  water  from  the  leaves,  thus  causing  a  strong 
upward  movement  of  the  water  which  contains  the  various 
solutions  of  food  matter.  Moreover,  there  can  be  no  doubt 
that  the  movement  of  the  water  in  terrestrial  plants,  caused 
by  the  swaying  and  bending  of  the  stems  and  branches, 
facilitates  and  hastens  the  diffusion  of  food  materials. 


CHAPTER    XI. 

CHEMICAL  PEOCESSES  IN  THE  PLANT. 
§  I.    ASSIMILATION. 

231. — In  many  plants  the  food  materials  which  are  taken 
into  the  plant-body  are  of  such  a  nature  that  they  can  be 
directly  used  by  the  protoplasm ;  thus  in  the  saprophytes 
the  solutions  of  organic  compounds  derived  from  the  decay 
of  animal  or  vegetable  tissues  are  imbibed  by  the  protoplasm 
and  used  by  it  as  true  food  ;  and  in  the  parasites  the  proto- 
plasm and  the  juices  of  living  tissues  are  directly  used  in  a 
similar  way.  It  is,  furthermore,  probable  that  in  some  of 
the  lowest  forms  of  vegetation,  as  in  the  Myxomycetes  and 
Schizomycetes,  the  protoplasm  is  capable  of  making,  to  a 
limited  extent,  a  direct  use  of  some  of  the  inorganic  sub- 
stances absorbed  by  them.  For  the  most  part,  however,  the 
principal  food  materials  taken  in  by  plants  are  such  as  can- 
not be  directly  used  by  protoplasm  in  either  its  vegetative 
or  reproductive  activity  ;  thus  neither  water  nor  carbon 
dioxide  is  directly  used  as  food  by  the  protoplasm  of  ordi- 
nary green  plants,  but  in  all  cases  they  undergo  certain 
chemical  changes,  by  which  they  are  made  suitable  for  use 
by  protoplasm.  To  these  preparatory  changes,  which  fit  the 
crude  food  materials  for  protoplasmic  food,  the  general  name 
of  Assimilation  has  been  given. 

232. — It  is  impossible  as  yet  to  give  a  complete  statement 
of  all  the  processes  in  assimilation  ;  the  principal  facts  now 
made  out  appear  to  be  as  follows  :  In  the  chlorophyll- 
bearing  portions  of  plants,  carbon  dioxide  and  water  are  de- 
composed, and  from  their  component  elements  carbohydrates 
are  at  once  formed.  This  decomposition  and  subsequent 
combination  take  place  only  in  the  granules  or  masses  of 


METASTASIS.  179 

chlorophyll,  and  only  in  sunlight.  Those  parts  of  ordinary 
plants  which  are  destitute  of  chlorophyll  are  entirely  want- 
ing in  the  power  of  assimilation,  and  likewise  the  chloro- 
phyll-bearing portions  are  unable  to  assimilate  in  darkness. 
Carbon  dioxide  is  probably  decomposed  into  carbon  oxide 
and  free  oxygen  :  C0a  —  CO  +  0.  At  the  same  time  water 
is  decomposed  into  hydrogen  and  oxygen  :  H,  0  =  2  H  + 
0.  The  free  oxygen  atoms  are  exhaled,  and  by  the  union 
of  carbon  oxide  and  hydrogen,  starch  is  in  most  cases 
formed ;  this  appears  as  minute  granules  imbedded  in  the 
chlorophyll-bodies  (Fig.  43,  p.  52).  In  some  plants  no 
starch  is  formed  in  the  chlorophyll,  but  oily  or  sugary  mat- 
ters which  have  nearly  the  same  chemical  significance. 
Assimilation  is  thus  a  deoxidizing  process.  Both  water  and 
carbon  dioxide  contain  large  quantities  of  oxygen,  while  in 
starch  it  is  much  less  ;  consequently,  in  the  formation  of  the 
latter  from  the  former,  there  must  be  a  "surplus  of  oxygen. 
This  may  be  shown  as  follows  : 

12  CO      -     13CO 1  Starch 

LA  L/UH    —     ion) 

Jloj-  =240  set  free.  1=  CiaHaoO10  +  2HaO. 
24  H J 

Here  twelve  molecules  of  carbon  dioxide  and  twelve  mole- 
cules of  water  produce  one  molecule  of  starch  and  two  mole- 
cules of  water  (water  of  organization.),  while  twenty-four 
atoms  of  oxygen  are  set  free  and  permitted  to  escape  from 
the  cells  into  the  surrounding  air  or  water. 

§  II.  METASTASIS. 

233.— Its  General  Nature.  The  chemical  changes  just 
described,  which  constitute  assimilation,  take  place  only  in 
chlorophyll-bearing  plants,  or  parts  of  plants,  and  in  these 
only  in  the  sunlight.  In  cells  which  are  destitute  of  chloro- 
phyll, and  in  the  chlorophyll-bearing  ones  in  the  absence  of 
light,  other  chemical  changes  take  place  ;  these,  while  differ- 
ing much  among  themselves,  agree  in  always  being  processes 
of  oxidation,  and  changes  of  one  organic  compound  into  an- 
other. To  these  chemical  changes,  in  order  to  distinguish 


180  SOT  ANT, 

them  from  those  of  assimilation,  the  term  Metastasis*  has 
been  applied. 

It  is  even  more  difficult  to  give  anything  like  a  complete 
account  of  the  processes  of  metastasis  than  of  those  of  assim- 
ilation ;  all  that  can  be  done  is  to  indicate  the  general  nature 
of  the  chemical  changes  which  are  best  known. 

234.— Transformation  of  Starch.  In  darkness  the  starch 
which  had  previously  formed  in  the  chlorophyll-bodies  at 
once  undergoes  changes  which  render  it  soluble,  allowing  it 
to  diffuse  to  other  parts  of  the  plant  with  great  freedom. 
The  nature  of  these  changes  appears  to  vary  somewhat  in 
different  plants,  but  they  consist  essentially  in  the  transform- 
ation of  the  insoluble  starch  into  a  chemically  similar  but 
soluble  substance.  Glucose  (0,,  H.,4  Oia),  inuline  (CJ2  IIao  010), 
and  cane  sugar  (Cia  HM  On)  are  the  more  common  of  the 
soluble  substances  so  formed,  and  one  or  other  of  these  may 
frequently  be  detected  in  the  adjacent  cells  after  the  disap- 
pearance of  the  starch  from  the  chlorophyll. 

235.— The  Nutrition  of  Protoplasm.  These  diffusing  as- 
similated matters  are  imbibed  by  the  protoplasm  of  the  living 
tissues,  and  constitute  its  most  important  food.  In  connec- 
tion with  the  nitrates  and  sulphates,  also  imbibed,  it  fur- 
nishes the  materials  for  the  increase  of  protoplasmic  sub- 
stance in  growing  cells.  The  exact  changes  which  take 
place  in  the  formation  of  protoplasm  are  unknown,  but  it  is 
probable  that  a  portion  of  the  soluble  assimilated  matter 
(glucose,  inuline,  etc.)  is  broken  up  by  the  action  of  oxygen 
into  carbon  dioxide  and  one  of  the  organic  acids  (e.g.,  oxalic 
acid) ;  and  the  latter,  by  replacing  the  acids  in  the  sulphates 
and  nitrates,  may  set  free  the  sulphur  and  nitrogen  necessary 
to  the  formation  of  protoplasm.  The  occurrence  of  crystals 
of  calcium  oxalate  in  the  tissues  of  many  plants  rather  indi- 
cates the  probability  of  this  or  a  similar  series  of  reactions. 


*  Literally  "  to  place  in  another  way,"  from  the  Greek  fierd  beyond, 
or  over,  and  lardvai,  to  place.  We  owe  the  present  application  of  the 
word  to  Professors  Bennett  and  Dyer,  who  used  it  as  the  equivalent 
of  the  German  "  Stoff  wechsel "  in  their  English  translation  of  Sachs' 
"Lehrbuch." 


METASTASIS.  181 

236.—  The  Storing  of  Reserve  Material.  In  many  plants 
the  surplus  of  assimilated  matter  is  stored  up  in  one  or  more 
organs  as  reserve  material  ;  thus  in  the  potato  the  starch 
formed  in  the  leaves  in  sunlight  is,  in  darkness,  transformed 
into  glucose,  or  a  substance  very  nearly  like  it,  and  in  this 
soluble  form  it  is  diffused  throughout  the  plant,  and  in  the 
underground  stems  (tubers)  is  again  transformed  into  starch. 
So  in  the  case  of  many  seeds  a  mass  of  reserve  material  is 
stored  up,  generally  in  the  form  of  starch  (e.g.,  the  cereal 
grains),  and  sometimes  in  the  form  of  oily  matters  (e.g.,  the 
seeds  of  Cruciferse,  Flax,  Castor  Bean,  Cucurbitaceae,  etc.). 
In  the  storing  of  starch  a  notable  feature  of  the  changes  which 
take  place  is  the  apparent  addition  and  subtraction  of  one 
or  two  molecules  of  water  ;  it  is  probable,  however,  that  in 
the  transformation  of  starch  to  glucose  oxygen  combines 
with  some  of  the  carbon,  forming  free  carbon  dioxide,  as 
follows  : 

6  (C(1  Hao  010)  +  24  0  =  5  (C15  HM  Olf  )  +  12  CO,. 

The  transformation  of  glucose  to  starch  may  be  a  simple 
process  of  breaking  up  of  a  molecule  of  the  former  into  starch 
and  two  molecules  of  water,  as  follows  : 


In  the  storing  of  oily  matters  it  is  probable  that  these  are 
formed  at  the  expense  of  the  starch,  and  that  they  are  the 
results  of  subsequent  deoxidation. 

237.—  The  Use  of  Reserve  Material.  In  the  use  of  re- 
serve material,  as  in  the  germination  of  a  starchy  seed,  the 
starch  appears  to  undergo  a  change  exactly  like  that  in  its 
disappearance  from  chlorophyll.  Here  it  is  certain  that  oxy- 
gen is  absorbed,  and  that  carbon  dioxide  is  evolved,  while 
the  starch  is  transformed  into  glucose  (see  the  reaction  above) 
Similar  transformations  doubtless  take  place  in  the  use  of 
the  starch  stored  up  in  buds,  twigs,  stems,  bulbs,  etc.  In 
the  germination  of  oily  seeds,  after  the  absorption  of  oxy- 
gen, starch  is  (in  many  cases,  at  least)  first  produced,  and 
from  this  the  soluble  sugar  is  formed.  In  any  case,  after  the 
solution  is  attained  the  subsequent  metastatic  changes  are 


182  BOTANY. 

similar  to  those  which  follow  the  transformation  of  the 
starch  of  the  chlorophyll. 

238.— The  Nutrition  of  Parasites  and  Saprophytes  is 
similar  to  that  of  embryos,  buds,  bulbs,  etc.  Here  assimi- 
lated materials  are  drawn  from  some  other  organism,  and 
subsequently  undergo  metastatic  changes.  In  some  cases  the 
parasitism  is  only  partial,  as  in  the  mistletoe,  where  a  part 
of  the  assimilated  matter  is  formed  in  the  parasite  (which, 
therefore,  contains  chlorophyll),  while  a  portion  seems  to  be 
taken  along  with  the  mineral  salts  from  the  host  plant.  So, 
too,  there  are  plants  which  are  partially  saprophytic  in  habit, 
deriving  a  part  of  their  nourishment  as  saprophytes,  while 
the  remainder  is  elaborated  by  their  chlorophyll.  Many  cul- 
tivated plants,  as  we  grow  them,  are  partially  saprophytic, 
deriving  a  portion  of  their  nourishment  from  decaying  or- 
ganic matter  in  the  soil.  The  so-called  Carnivorous  plants, 
as  Drosera,  Dionaea,  Sarracenia,  Darlingtonia,  Nepenthes, 
Utricularia,  etc.,  are  in  reality  partially  saprophytic,  obtain- 
ing a  considerable  part  of  their  food  materials  from  de- 
caying animal  matter. 

239.— The  Formation  of  Alkaloids.  Among  the  most 
obscure  of  the  metastatic  changes  are  those  which  give  rise 
to  the  alkaloids.  These  are  compounds  of  carbon,  hydro- 
gen, nitrogen,  and  generally  oxygen,  in  which  the  first  two 
elements  have  approximately  an  equal  number  of  atoms, 
while  the  last  two  have  also  a  nearly  equal  but  much  smaller 
number. 

The  more  important  ones  are  the  following  : 

Conia  (C8  H,5N,)  from  Conium. 
Nic»tine  (C10  H14N2)  from  Tobacco. 
Cinchonia  (CSoHa4  NaO)  from  Peruvian  Bark. 

Morphia  (C17  H,»  N03  +  Ha  O)  from  the  Opium  Poppy. 
Strychnia   (Cai  H2a  N2  Oa)  from  the  seeds  of  Strychnos. 
Caffeine  (C8  H10  N4  Oa  +  Hs  O)  from  Coffee  and  Tea. 

These  and  many  others  occur  in  plants  in  combination 
with  organic  acids,  such  as  :  malic  acid  (C4  He  05)  ;  tartaric 
acid  (C4  H9  0B)  ;  citric  acid  (C9  H8  0,)  ;  oxalic  acid  (C.,  II 
04);  tannic  acid  (C,7  Haa  017) ;  quinic  acid  (C,  H12  06) ; 
meconic  acid  (C,  H4  0.)-  These  acids  are  probably  formed 


METASTASIS.  183 

by  the  oxidation  of  some  of  the  saccharine  or  amylaceous 
substances  in  the  plant,  while  the  alkaloids  with  which  they 
are  combined  appear  to  have  some  relation  to  the  nitrogenous 
constituents  of  the  protoplasm,  and  are  possibly  formed  like 
them.  From  the  fact  that  the  alkaloids  are  formed  more 
abundantly  in  those  tissues  which  have  passed  the  period  of 
their  greatest  activity,  it  may  be  surmised  that  they  are 
either  compounds  of  a  lower  grade  which  are  formed  instead 
of  the  ordinary  albuminoids,  or  the  first  results  of  the  incip- 
ient decay  of  the  cells. 

240.— Results  of  Metastasis.  In  the  preceding  para- 
graphs it  is  seen  that  chlorophyll-bearing  plants  absorb 
carbon  dioxide  and  exhale  free  oxygen,  the  former  being  de- 
composed in  the  chlorophyll  granules  in  sunlight  and  the 
oxygen  being  set  free  as  a  consequence.  In  other  words,  the 
absorption  of  carbon  dioxide  and  the  exhalation  of  oxygen 
are  connected  with  the  process  of  assimilation.  It  is  further 
seen  that  oxygen  is  absorbed  and  carbon  dioxide  evolved,  as 
results  of  certain  metastatic  processes  which  take  place  in 
any  tissues,  whether  possessing  chlorophyll  or  not,  and  inde- 
pendently of  the  presence  or  absence  of  sunlight.  In  the 
sunlight  the  absorption  of  carbon  dioxide  to  supply  assimila- 
tion is  so  greatly  in  excess  of  its  exhalation  as  a  result  of 
metastatic  action,  that  the  latter  is  unnoticed.  In  dark- 
ness, however,  when  assimilation  is  stopped,  the  exhalation 
of  carbon  dioxide  becomes  quite  evident.  So,  too,  with 
oxygen  ;  in  the  sunlight  the  excess  of  its  evolution  is  so 
great  over  its  absorption  that  the  latter  was  long  unknown  ; 
but  in  the  absence  of  light  its  absorption  becomes  manifest. 
Parasites  and  saprophytes,  as  well  as  those  parts  of  ordinary 
plants  which  are  wanting  in  chlorophyll,  as  flowers" and  many 
fruits,  deport  themselves  in  this  regard  exactly  as  chloro- 
phyll-bearing organs  do  in  darkness. 


CHAPTER   XII. 

THE    RELATIONS    OF    PLANTS    TO    EXTERNAL 
AGENTS. 

§  I.   TEMPEEATURE. 

241.— General  Relations.  The  functions  of  plants  are 
possible  only  between  certain  limits  of  temperature  of  the 
air,  water,  or  soil,  varying  considerably  for  each  species.  In 
every  plant  there  is  a  certain  minimum  temperature,  below 
which  all  functional  activity  ceases  ;  thus  in  most  instances 
plants  become  inactive  when  the  temperature  approaches 
0°  Cent.  (32°  Fahr.).  On  the  other  hand,  there  is  a  maxi- 
mum beyond  which  activity  ceases  ;  this  ranges  in  different 
plants  from  about  35°  to  50°  Cent.  (95°  to  122°  Fahr.).  Be- 
tween these  two  extremes  is  the  temperature  at  which  the 
greatest  activity  takes  place  ;  this  has  been  termed  the  opti- 
mum. 

In  any  particular  plant,  the  maxima,  optima,  and  minima 
are  not  exactly  alike  for  all  functions,  some  being  performed 
at  temperatures  considerably  above  or  below  those  at  which 
others  cease.  It  is  furthermore  to  be  observed  that,  in  gen- 
eral, there  is  a  simple  suspension  of  activity  at  temperatures 
a  few  degrees  below  the  minimum,  whereas  above  the  max- 
imum the  death  of  the  organ  ensues  ;  in  the  former  a  resto- 
ration of  the  normal  temperature  is  soon  followed  by  a  re- 
sumption of  activity ;  in  the  latter  the  activity  cannot  be 
restored,  even  under  the  most  favorable  conditions. 

242.— Absorption  of  Water  as  Affected  by  Temperature. 
The  absorption  of  water  and  watery  solutions  is  greatly 
affected  by  changes  in  the  temperature  of  the  absorbing 
organs,  as  the  roots  of  the  higher  plants.  Thus  Sachs 
found  "that  the  roots  of  the  tobacco-plant  and  gourd  no 


TEMPERATURE.  185 

longer  absorb  sufficient  water  to  replace  a  small  loss  by  evap- 
oration in  a  moist  soil,  having  a  temperature  of  from  3°  to 
5°  Cent.  (37°  to  41°  Fahr.) ;  the  heating  of  the  soil  to  a  tem- 
perature of  from  12°  to  18°  Cent.  (53°  to  64°  Fahr.)  sufficed 
to  raise  their  activity  to  the  needful  extent."*  According 
to  the  same  investigator,  the  roots  of  the  turnip  and  cabbage 
continue  to  absorb  water,  even  when  the  temperature  of  the 
soil  is  reduced  very  nearly  to  0°  Cent.  (32°  Fahr.).  In  the 
winter  and  early  spring,  when  the  temperature  of  the  soil  is 
low,  the  roots  of  trees  and  other  perennials  cannot  absorb 
moisture  unless  they  extend  deep  enough  to  reach  the 
warmer  strata  beneath  ;  under  such  circumstances,  it  not  in- 
frequently happens  that  if  the  air  temperature  rise  high 
enough  to  allow  evaporation,  evergreen  trees  and  shrubs  are 
killed  by  too  great  loss  of  moisture. 

243.— Evaporation  or  Transpiration.  In  aerial  plants, 
when  the  temperature  of  the  air  is  low,  but  little  evaporation 
takes  place  from  the  leaves  or  other  living  organs,  while  an 
increase  of  temperature  is  followed  by  an  increase  in  the 
rapidity  of  evaporation.  It  is  probable  that  this  is  due  (1st) 
to  the  closing  of  the  stomata  in  the  lower,  and  their  opening 
in  the  higher  temperature,  and  (3d)  to  the  fact  that  in  all 
ordinary  cases,  as  the  temperature  of  the  air  is  lowered  its 
degree  of  saturation  is  increased,  and  as  its  temperature  is 
raised  its  degree  of  saturation  is  decreased.  As  transpiration 
appears  to  be  a  purely  physical  phenomenon,  we  scarcely 
need  expect  it  to  be  as  definitely  or  certainly  affected  by 
changes  of  temperature  as  are  the  proper  functions  of  the 
plant. 

244.— Assimilation.  The  lower  limit  of  the  temperature 
in  which  assimilation  is  possible  varies  much  in  different 
plants.  The  "Ked-snow  Plant"  (Protococcus,  sp.)  of  the 
Arctic  regions  grows  rapidly  upon  the  surface  of  the  snow  in 
a  temperature  which  must  be  little,  if  any,  above  0°  Cent. 
(32°  Fahr.)  ;  in  the  larch,  assimilation  takes  place  at  from 
0.5°  to  2.5°  Cent.  (33°  to  36°  Fahr.),  and  in  meadow-grasses 
at  from  1.5°  to  3.5°  Cent.  (35°  to  38°  Fahr.).  In  water- 

*  "  Lehrbuch,"  English  edition,  p.  652. 


186  SOTANT. 

plants  the  lower  temperature  limit  is  apparently  somewhat 
higher  than  in  aerial  ones  ;  thus  in  Hottonia  palustris  it  is 
2.7°  Cent.  (37°  Fahr.) ;  in  VaUisneria,  6°  Cent.,  or  more  (42° 
Fahr.)  ;  in  Potamogeton  from  10°  to  15°  Cent.  (50°  to  59° 
Fahr.). 

Neither  the  maximum  nor  the  optimum  temperature  has 
been  determined  for  ordinary  land  plants  ;  in  Hottoniu 
palustris,  an  aquatic  plant,  the  maximum  temperature  for 
assimilation  is,  according  to  Sachs,  between  50°  and  56° 
Cent.  (122°  and  132°  Fahr.). 

245.— Metastasis.  But  little  is  accurately  known  as  to 
the  effect  of  an  increase  or  decrease  of  temperature,  within 
moderate  ranges,  upon  those  metastatic  changes  which  take 
place  in  the  ordinary  growth  of  plants  or  the  storing  of  reserve 
material.  It  is  well  known,  however,  that  some  plants  live 
wholly  in  low  temperatures,  performing  all  their  functions 
in  air  or  water  little,  if  any,  above  the  freezing  point. 
Thus  in  the  "  Eed-snow  Plant,"  above  cited,  the  metas- 
tatic changes  must  take  place  very  near  0°  Cent. 

In  the  polar  waters,  where  the  temperature  is  from  3°  to 
5°  Cent.  (37°  to  41°  Fahr.),  or  even  less,  myriads  of  diatoms 
flourish,  and  in  seas  but  little  warmer  many  of  the  higher 
sea-weeds  (Fucaceae  and  Florideae)  abound.  In  all  these 
cases  the  metastatic  changes  (as  well  as  all  others)  must  take 
place  at  these  low  temperatures.  In  ordinary  land-plants  it 
is  to  be  observed  that  whereas  assimilation  takes  place  only 
during  the  light  part  of  the  day,  when  it  is  warmer,  metasta- 
sis takes  place  not  only  in  daylight,  but  even  more  rapidly  in 
darkness,  when  the  temperature  is  considerably  lower.* 

Sachs  measured  the  length  of  plumule  developed  upon 
different  plants  of  the  same  species  subjected  to  different 
temperatures,  and  in  this  way  found  the  approximate  optima 
for  several  species,  as  follows  :f 

*  It  must  not  be  forgotten,  however,  that  assimilation  is  dependent 
upon  light,  while  metastas's  is  somewhat  checked  by  it,  and  this  is 
doubtless  by  far  the  most  important  relation  ;  and  still  it  is  a  significant 
fact  that  in  ordinary  land-plants  metastasis  continues  when  assimi- 
lation has  stopped. 

fin  " Physiologische  Untersuchungen  tiber  die  Abhangigkeit 


TEMPERA  TURE. 


187 


Pea 26°  Cent.  (78.8°  Fahr.). 

Wheat  (winter  var.).." 34°      "      (92.7°      " 

Indian  corn 34°      "     (92.7°      " 

Scarlet  Bean 34°      "      (92.7° 

In  Sachs'  and  others'  observations  upon  the  growth  of 
roots,  it  was  found  that  the  most  rapid  growth  took  place 
for  different  plants  at  the  following  temperatures  : 

Scarlet  Bean 26°  Cent.  (78.8°  Fahr.). 

Pea 26.6°  "     (79.9°     " 

Flax 27.4°"     (81.3°     " 

Wheat  (winter  var.) -. 28.5°"      (83.3°     " 

Barley  (summer  var.) 28.5°  "      (83.3°      " 

Indian  corn 34°      "     (92.7°     " 

In  the  deposit  of  reserve  material  there  can  be  no  doubt 
that  metastasis  often  takes  place  at  lower  temperatures  than 
assimilation  ;  thus  the  storing  of  starch  in  the  potato  tubers, 
and  in  many  other  subterranean  stems  and  roots,  takes  place 
in  the  soil  which,  at  the  time,  is  much  cooler  than  the  air. 

In  the  growth  of  many  plants  in  early  spring,  at  the  ex- 
pense of  reserve  material  in  the  roots  or  stems,  the  metas- 
tatic  changes  often  take  place  at  quite  low  temperatures. 
Thus  perennial  and  biennial  rooted  plants,  as  many  grasses, 
thistles,  parsnips,  etc.,  begin  to  grow  almost  as  soon  as  the 
snow  has  disappeared,  and  the  flower  buds  of  many  perenni- 
als develop  equally  early — e.g.,  the  hazel,  elm,  maple,  liver- 
leaf  (Hepatica),  Mayflower,  etc. 

As  regards  the  metastatic  changes  which  take  place  in  the 
germination  of  seeds,  we  have  much  more  definite  informa- 
tion. Sachs  has  determined  the  minimum,  optimum,  and 
maximum  temperatures  for  the  germination  of  the  seeds  of 
the  following  plants  :* 


MINIMUM. 

OPTIMUM. 

MAXIMUM. 

I  nd.  corn. 
Scar.  B'n.. 
Pumpkin. 
Wheat.  .  . 
Barley.  .  . 

9.4°  C.=  (48.8°  F.). 
9.4°C.=  (43.8°  F.). 
14°    C.=  (56.7°  F.). 
5°     C.=  (41°     F.). 
5°    C.=  (41°     F.). 

34°  C.  =  (92  .7° 
34'  C.  =  (92.7° 
34°  C.  =(92.7° 
29°  C.  =  (83.7° 
29°  C.  =  (83.7° 

F.).  46°  C.  =  (115.2°  F.). 
F.).46°C.  =  (115.2°  F.). 
F.).46°  C.  =  (115.2°  F.) 
F.).  42°  C.  =  (108.5°  F.). 
F.).  37°  C.  =  (  99.5°  F.). 

Keimung  von  der  Temperature,"  in  "  Pringsheim's  Jahrbllcher  fiir 
Wiasenschaftliclie  Botanik,"  Vol.  II.,  1860,  p.  354. 
*  "  Pliysiologische  Untereuchungen,"  etc.,  op.  cit.,  p.  365. 


188 


BOTANY. 


According  to  several  observers,  the  minima  and  optima 
for  the  germination  of  the  seeds  of  the  following  plants  are  : 


MINIMUM. 

OPTIMUM. 

Lepidium  sativum.  .  .  . 
Flax 

1.8°  C.  =  (35°  Fahr.). 
1.8°  C.  =  (35°      " 
0.0°  C.  =  (32°      " 
0.7°  C.  =  (43°      " 

27.4°  C.    =  (81°  Fa 
27.4°  C.    =   (81° 
27.4°  C.    =  (81° 
26.6°  C.    =  (80° 
31.5°   <  .    =  (88.7° 
31.5°  C    =  (88.7° 
31.5°  C.    =  (88.7° 
37.5°  C.    =  (99.5° 

hr.). 

White  Mustard  
Pea     . 

Pole  Bean. 

Sunflower  . 

Hemp  

Watermelon  

246.— Death  Caused  by  High  Temperature.  When  the 
temperature  rises  above  a  certain  point  the  death  of  the 
plant  takes  place.  Those  plants,  or  parts  of  plants,  which 
contain  the  least  water  are  capable  of  enduring  higher  tem- 
peratures than  those  which  are  more  watery.  Thus  at  from 
65°  to  80°  Cent.  (149°  to  177°  Fahr.)  many  dry  spores  and 
seeds  are  uninjured,  while  in  water  they  are  generally  killed 
when  the  temperature  exceeds  50°  or  55°  Cent.  (122°  or  131° 
Fahr.).  For  ordinary  growing  parts  of  plants  the  tempera- 
ture must  be,  as  a  rule,  considerably  lower  than  those  given 
above.  Few  aquatic  plants  can  endure  a  prolonged  tempera- 
ture much,  if  any,  above  40°  Cent.  (104°  Fahr.),  and  at  50° 
Cent.  (122°  Fahr.)  most  terrestrial  plants  are  soon  killed. 
It  appears,  also,  that  at  temperatures  much  lower  than  these 
some  plants  are  killed  ;  thus,  according  to  Hofmeister,*  the 
organization  of  the  protoplasm  of  the  plasmodium  of  Didy- 
mium  serpula  (one  of  the  Slime  Moulds)  is  destroyed  by 
heating  it,  in  air,  to  35°  Cent.  (95°  Fahr.),  and  in  the  nearly 
related  Fuligo  varians  the  same  destruction  follows  at  39° 
Cent.  (102°  Fahr.). 

The  immediate  cause  of  death  appears  to  be  the  coagula- 
tion of  the  albuminoids  of  the  protoplasm.  The  protoplasm 
thus  loses  its  power  of  imbibing  Avater,  and  the  cells  conse- 
quently lose  their  turgidity.  In  watery  tissues  chemical 
changes  at  once  begin,  resulting  in  the  rapid  disintegration 


*  "  Die  Lehre  von  der  Pflanzenzelle,"  1867,  p.  27. 


TEMPERATURE.  Ib9 

of  the  substances  in  the  cells,  accompanied  by  an  evolution 
of  carbon  dioxide. 

247.— Death  Caused  by  Low  Temperature.  In  many 
respects  the  results  of  too  great  a  reduction  of  temperature 
are  similar  to  those  produced  by  too  great  an  elevation. 
There  is  observed  the  same  coagulation  of  the  albuminoids, 
resulting  in  the  destruction  of  the  power  of  the  protoplasm 
to  imbibe  water,  and,  as  a  consequence,  in  the  loss  of  the  tur- 
gidity  of  the  cells.  Moreover,  as  in  the  case  of  injury  from 
high  temperature,  those  cells  which  are  the  most  watery  are 
the  ones  which,  other  things  being  equal,  are  injured  most 
quickly  by  a  reduction  of  temperature.  Embryo  plants  in 
seeds,  when  dry,  are  able  to  endure  almost  any  degree  of  low 
temperature  ;  but  after  they  have  germinated,  and  the  cells 
have  become  watery,  they  are  generally  killed  by  a  reduction 
to,  or  a  few  degrees  below,  0°  Cent.  (32°  Fahr.).  So,  too, 
the  comparatively  dry  tissues  of  the  winter  buds  and  ripened 
stems  of  the  native  trees  and  shrubs  in  cold  countries  are 
rarely  injured  even  in  the  severest  winters,  while  the  young 
leaves  and  shoots  in  the  spring  are  often  killed  by  slight 
frosts. 

Death  from  low  temperature  is  always  accompanied  by  the 
formation  of  ice-crystals  in  the  succulent  tissues  ;  these  are 
formed  from  the  water  of  the  plant,  which  is  abstracted  from 
it  in  the  process  of  congelation.  Much  of  the  water  thus 
frozen  is  that  which  fills  the  cavities  (vacuoles)  of  the  cells, 
while  some  of  it  is  that  which  moistens  the  protoplasm  and 
cell- walls.  Now  it  is  evident  that  the  water  in  the  large 
vacuoles  is  much  more  easily  congealed  than  that  in  the  pro- 
toplasm and  cell- walls  ;  for  in  the  latter  the  force  of  adhesion 
between  the  molecules  of  protoplasm  or  cellulose  and  the 
imbibed  water  offers  a  considerable  resistance  to  the  separa- 
tion of  the  water  in  ice-crystals,  and  this  resistance  is  greater 
as  the  contained  water  is  less.  As  the  liquid  in  the  vacuoles 
is  not  pure  water,  but  a  mixture  of  several  solutions,  it  freezes 
at  a  lower  temperature  than  water,  and  then,  according  to  a 
well-known  law  of  physics,  separates  into  pure  ice-crystals 
and  a  denser  unfrozen  solution.  By  a  greater  reduction  of 
temperature  more  ice-crystals  may  be  separated  out,  and  the 


190  BOTANY. 

remaining  solution  made  denser  still.  These  adhesive  forces 
tend  to  retard  the  formation  of  ice-crystals,  and  it  is  prob- 
able that  it  is  only  in  extremely  low  temperatures,  if  at  all, 
that  the  liquids  in  the  plant  are  completely  solidified. 

248. — A  plant  which  has  been  frozen  may  survive  in  many 
instances  if  thawed  slowly,  whereas  if  thawed  quickly  its 
vitality  is  generally  destroyed.  Thus  many  herbaceous 
plants  will  endure  quite  severe  freezing  if  they  are  afterward 
covered  so  as  to  secure  a  slow  rise  of  the  temperature,  and 
many  bulbs,  tubers,  and  roots  will  survive  the  severest  win- 
ters if  covered  deeply  enough  to  prevent  sudden  thawing. 
Likewise  turgid  tissues,  which  are  not  living,  as  those  of 
many  succulent  fruits,  are  injured  or  not  by  freezing,  accord- 
ing as  the  thawing  has  been  rapid  or  slow.  From  these  facts 
it  may  be  inferred  that  the  injury  in  freezing  is  primarily  of 
a  physical  instead  of  a  chemical  nature,  and  that  it  is  mainly 
the  withdrawal  of  water  from  its  physical  union  with  the 
solids  of  the  cell.  According  to  this  view,  the  difference  be- 
tween slow  and  rapid  thawing  is  that  in  the  former  the 
slowly  liquefying  water  is  reabsorbed  by  the  same  solids  from 
which  it  had  been  abstracted,  while  in  the  latter  the  large 
amount  of  water  set  free  is  imperfectly  absorbed,  forming 
solutions  which  are  unstable  and  subject  to  subsequent  fer- 
mentive  changes.  It  is  probable  that  to  these  fermentive 
changes  is  due  the  coagulation  of  the  albuminoids  and 
the  rapid  disorganization  of  the  protoplasm  which  accom- 
pany injury  from  freezing. 

While  the  sketch  given  above  is  doubtless  true  in  a  large 
number  of  cases,  it  appears  that  in  many  other  cases  death 
follows  freezing  whether  the  thawing  be  rapid  or  not  ;  and 
this  indicates  that  besides  the  immediate  causes  of  death  al- 
ready indicated,  there  are  others  which  are  as  yet  unknown 
to  us. 

§  II.  LIGHT. 

249.— General  Relations.  Directly  or  indirectly  plant- 
life,  as  indeed  all  life,  whether  vegetable  or  animal,  is  de- 
pendent upon  light.  Parasites  ;ind  saprophytes  may  grow 


LIGHT.  191 

in  complete  darkness,  but  they  do  so  at  the  expense  of  ma- 
terial which  has  beeii  elaborated  in  light.  So,  too,  sonic 
parts  of  many  ordinary  plants  grow  in  total  darkness,  as 
roots,  tubers,  bulbs,  etc.,  but  these  depend  for  their  carbo- 
hydrates upon  the  aerial,  chlorophyll-bearing  parts  which 
are  in  the  light.  As  will  be  shown  in  the  sequel,  this  depen- 
dence of  all  life  upon  light  is  due  to  its  relation  to  chloro- 
phyll in  the  processes  of  assimilation  ;  and  while  other  func- 
tions than  that  of  assimilation  and  other  orgars  than  those 
which  contain  chlorophyll  are  somewhat  affected  by  the 
presence  or  absence  of  light,  or  its  greater  or  less  intensity, 
yet  these  latter  are  of  comparatively  little  moment  when  com- 
pared with  the  former. 

The  absorption  of  water  by  the  plant  appears  to  be  entirely 
independent  of  light,  and  in  most  plants  it  takes  place  in  its 
entire  absence.  Likewise  it  is  probable  that  light  itself  does 
not  directly  affect  the  rate  of  evaporation  of  water  from  the 
leaves  of  higher  plants.  As,  however,  the  stornata  are  gen- 
erally opened  more  widely  in  light  than  in  darkness,  evapo- 
ration may  be  promoted  by  it  in  some  cases. 

250.— Light  and  Assimilation.  It  is  first  of  all  to  be 
observed  that  chlorophyll  itself  is  dependent  upon  light. 
Those  parts  of  plants  (with  rare  exceptions)  which  grow  in 
darkness  are  destitute  of  chlorophyll,  and  even  parts  which 
contain  chlorophyll  lose  it  when  placed  for  some  time  in  com- 
plete darkness.  When  such  a  colorless  plant  is  brought  into 
the  light  it  soon  becomes  green  from  the  formation  of  chlo- 
rophyll in  its  protoplasm. 

The  decomposition  of  carbon  dioxide,  and  the  consecpient 
evolution  of  oxygen,  only  take  place  in  the  light.  As  the 
light  decreases  in  intensity  from  a  certain  point  the  amount 
of  assimilation  decreases  ;  on  the  other  hand,  there  is  a  de- 
crease in  assimilation  as  the  intensity  increases  unduly,  and 
beyond  certain  points  in  either  direction  assimilation  ceases. 
Thus  there  are  here,  as  in  the  case  of  temperature,  a  mini- 
mum, optimum,  and  maximum  ;  but  we  cannot  define  their 
limits  as  readily,  for  want  of  a  proper  instrument. 

251. — Experiments  have  often  been  made  upon  plants 
when  placed  in  rays  of  different  refrangibility,  and  it  has 


192  BOTANY. 

been  shown  (1)  that  the  assimilation  is  greater  in  the  whole 

beam  (white  light)  than  in  any  one  of  its  constituent  rays, 

and  (2)  that  the  amount  of  assimilation  varies  greatly  in  the 

different  rays.*     When  plants  are  grown  in   the  different 

rays  of  the  spectrum,  and  properly  protected,  so  that  each 

receives  but  one  kind  of  light,  the  amount  of  assimilation  in 

each  case  is  aboiit  as  follows,  that  for  white  light  being  100  : 

Red,       Orange,       Yellow,       Green,       Blue,       Indigo,       Violet, 

9.5  23.5  37.3  14.  8.2  5.  2.5 

The  less  refrangible  rays  are  thus  seen  to  be  far  more  effica- 
cious than  the  more  refrangible  ones,  and  in  the  yellow  and 
orange  rays,  which  are  the  brightest  to  the  eye,  the  greatest 
amount  of  assimilation  takes  place.  From  these  rays  there 
is  a  decrease  toward  each  end  of  the  visible  spectrum,  and  in 
the  so-called  heat  rays  and  chemical  rays,  found  respectively 
beyond  the  red  on  the  one  hand  and  the  violet  on  the  other, 
there  is  no  assimilation  whatever. 

252.— Light  and  Metastasis.  Many  of  the  metastatic 
changes  in  the  plant  take  place  in  complete  darkness,  such 
as  those  connected  with  the  growth  of  roots  and  other  sub- 
terranean organs.  In  trees  and  thick-barked  shrubs  the  metas- 
tatic changes  which  occur  in  the  stems  are  in  total  darkness, 
and  even  in  many  herbs  the  thick  cortical  tissues  must  cut 
off  the  greater  part  of  the  light  from  the  active  interior  cells. 
On  the  other  hand,  in  a  great  number  of  aquatic  plants  their 
translucency  is  so  great  that  every  internal  change  must  be 
in  bright  light,  and  in  a  few  terrestrial  plants — as,  for  ex- 
ample, in  Impatient  Bahamina — the  cortical  tissues  permit 
most  of  the  light  to  penetrate  to  the  inner  active  cells.  These 
facts  indicate  a  marked  indifference  of  the  metastatic  changes 
to  light,  as  compared  with  those  of  assimilation. 

This  indifference  is  further  illustrated  in  the  growth  of 
flowers  in  the  dark,  where,  with  few  exceptions,  they  develop 
as  perfectly  as  in  the  light.  So  the  colorless  parasites — e.g., 
Monotropa,  Aphyllon,  Corallorhiza,  etc. — and  all  the  fungi 

*  The  earliest  experiments  of  much  value  were  those  of  Charles 
Daubeny,  "  On  the  Action  of  Lijrht  upon  Plants,  and  of  Plants  upon 
the  Atmosphere,"  pub.  in  Phil.  Trans.,  1836. 


HELIOTROPISM.  193 

grow  either  in  light  or  darkness.  It  must  not  be  inferred, 
however,  that  there  is  a  complete  indifference  to  the  presence 
or  absence  of  light,  for  careful  experiments  show  that  light 
favors  some  metastatic  changes,  while  in  many  cases  it  actu- 
ally exerts  a  retarding  influence.  Thus  if  all  other  condi- 
tions, as  temperature,  moisture,  etc.,  are  made  constant,  the 
rapidity  of  growth  of  most  aerial  stems  is  considerably  greater 
in  darkness  than  in  light ;  while  under  similar  conditions 
the  growth  of  the  leaves  of  most  plants  is  less.  Experiments 
show  that  the  retardation  of  growth  is  due  to  the  rays  of 
high  refrangibility,  blue,  indigo,  violet,  and  ultra  violet,  and 
that,  so  far  as  the  metastatic  changes  under  consideration 
are  concerned,  the  less  refrangible  rays  are  equivalent  to 
darkness. 

§  III.  HELIOTROPISM. 

253. — The  retarding  influence  of  light  upon  the  growth 
of  stems  gives  rise  to  a  curvature  when  the  illumination  is 
stronger  upon  one  side  than  upon  the  other.  Thus,  as  is 
well  known,  most  plants,  when  grown  in  windows,  bend 
strongly  toward  the  light,  and  if  their  position  be  afterward 
reversed  they  soon  bend  again  toward  the  side  of  greatest 
illumination.  To  this  phenomenon,  which  is  an  exceedingly 
common  one  throughout  the  vegetable  kingdom,  the  name 
Heliotropism*  has  been  given.  The  explanation  which  is 
commonly  given  is  that  the  light  retards  the  growth  on  the 
illuminated  side,  while  the  shaded  side  elongates,  resulting 
in  a  tension  which  necessarily  produces  a  curvature. 

254. — Evidently  allied  in  some  way  to  heliotropism  is  the 
bending  of  certain  organs  away  from  the  light.  Thus  the 
leafless  stems  (runners)  of  Saxifraga  sarmentosa,  when  grown 
in  a  window  so  that  they  are  illuminated  upon  one  side  more 
strongly  than  upon  the  other,  curve  toward  the  darker  side. 
This  opposite  bending  has  been  called  Negative  Heliotro- 
pism, and  is  supposed  to  be  caused  by  light  in  some  way  not 
yet  understood.  The  tendrils  of  the  Vine  and  Virginia 

*  From  the  Greek  #UoS,  the  sun,  and  rpeVetv,  to  turn. 


194  BOTANY. 

Creeper  (Ampelopsis)  are  negatively  heliotropic,  and  they 
are  thus  enabled  to  reach  and  attach  themselves  to  the  sur- 
faces— e.g.,  walls,  tree-trunks,  etc. — which  give  them  sup- 
port. The  same  organ  may  be  positively  heliotropic  in  one 
stage  of  its  growth  and  negatively  so  in  another  ;  thus  the 
younger  internodes  of  the  ivy  (Hedera)  bend  toward  the 
light,  and  the  older  ones  away  from  it ;  and  the  runners  of 
Saxifraga  sarmentosa,  mentioned  above,  are  positively  he- 
liotropic as  soon  as  they  develop  tufts  of  leaves  upon  their 
free  extremities. 

The  rays  of  light  which  cause  the  curvature  are  those 
having  the  greatest  refrangibility.  Sachs'  experiment  shows 
this  conclusively  ;  he  grew  plants  in  light  which  had  passed, 
on  the  one  hand,  through  a  solution  of  potassium  bichro- 
mate, and,  on  the  other,  through  one  of  ammoniacal  copper 
oxide ;  in  the  light  passed  through  the  first  solution  (red, 
orange,  and  yellow  rays,  and  a  portion  of  the  green)  there 
was  no  curvature  whatever,  while  in  the  blue,  indigo,  and 
violet  rays  passed  through  the  second  solution  the  heliotro- 
pic curvature  was  strongly  shown. 

§  IV.  GEOTKOPISM. 

255. — Nearly  all  organs  of  plants  have  a  definite,  normal 
direction  of  growth,  which  is  in  general  terms,  either  toward 
or  away  from  the  earth.  Thus  the  plasmodium  of  Fuligo 
varians  creeps  upAvard  ;  the  conidia-bearing  hyphse  of  moulds 
grow  upward,  while  the  root-like  hyphae  grow  downward  ;  the 
stems  of  many  mosses  grow  upward,  and  their  rhizoids  down- 
ward ;  in  the  higher  plants  the  stems,  as  a  rule,  grow  upward, 
some  root-stocks  and  other  stems  growing  downward,  how- 
ever, while  the  roots,  as  a  rule,  grow  downward.  To  these 
phenomena  of  growth  the  name  Geotropism*  has  been 
given  ;  when  the  direction  of  growth  is  downward,  the  organ 
is  said  to  be  positively  geotropic,  when  upward,  negatively 
geotropic. 

Knight  long  ago  proved  gravitation  to  be  the  cause  of 


*  From  tLe  Greek  yi),  yen,  the  earth,  and  rpt-irciv,  to  turn. 


GEOTROPISM.  195 

geotropism.*  He  placed  germinating  seeds  upon  wheels, 
which  were  made  to  rotate  rapidly,  in  one  series  of  experi- 
ments in  a  vertical,  and  in  the  other  in  a  horizontal  direction. 
In  the  first  case  he  found  that  the  roots  grew  directly  away 
from  the  centre  of  the  wheel,  and  the  stems  toward  it — that 
is,  having  in  his  experiment  substituted  centrifugal  force  for 
gravitation,  leaving  all  other  conditions  unchanged,  he  found 
that  the  root  grew  in  the  direction  of  that  force,  and  the 
stem  opposite  to  it.  In  the  second  series  of  experiments,  in 
which  gravitation  and  centrifugal  force  were  made  to  act  at 
right  angles  to  each  other  upon  the  growing  plantlets,  the 
direction  of  growth  coincided  with  that  of  the  diagonal  of 
the  two  forces,  the  roots  growing  diagonally  outward  and 
downward,  the  stems  inward  and  upward.  Dutrochet  after- 
ward showed,  by  similar  experiments,  that  many  leaves  are 
geotropic,  turning  their  under  surfaces  toward  the  circum- 
ference, and  their  upper  toward  the  centre  of  the  wheel,  f 

256. — If  positively  and  negatively  geotropic  organs  are 
placed  in  what  may  be  termed  their  normal  positions,  they 
grow  on  the  one  hand  downward  and  on  the  other  upward, 
without  any  curvature,  and  in  such  case  the  cells  in  all  parts 
of  any  section  of  either  the  ascending  or  descending  portions 
show  a  symmetrical  development.  But  if  such  symmetrically 
developed  positively  and  negatively  geotropic  organs  are  af- 
terward placed  in  a  reversed  or  horizontal  position,  they 
will  become  considerably  curved  in  order  to  assume  their 
normal  positions.  Thus  the  first  roots  of  most  young  plants, 
if  placed  horizontally,  soon  become  curved  downward  near 
their  tips  ;  this  takes  place  even  when  there  is  considerable 
resistance  to  the  curvature,  as  is  shown  by  the  penetration 
of  roots  into  mercury.  A  similar  curvature  in  an  upward 
direction,  however,  takes  place  in  most  stems  when  placed 
horizontally  ;  in  grasses  the  curvature  is  almost  entirely  con- 
fined to  the  nodes.  In  such  curved  parts  of  roots  and  stems 
the  cells'  are  more  elongated  upon  the  convex  than  upon 


*  "On  the  Direction  of  the  Radicle  and  Plumule  during  the  Vegeta- 
tion of  Seeds."    Philosophical  Transaction*,  1806. 
+  "  Memnims,"  Paris,  1837. 


1&6  BOTANY. 

the  concave  side,  and  it  is  evident  that  this  is  the  immediate 
cause  of  the  bending.  We  do  not,  however,  know  how  grav- 
itation causes  this  inequality  in  the  growth  of  the  cells, 
and  the  problem  is  the  more  difficult  from  the  fact  that  the 
more  rapid  elongation  of  the  cells  is  in  one  case  upon  the 
upper  and  in  the  other  upon  the  under  side  of  the  organ. 
Moreover,  in  "weeping trees"  the  branches  are  positively,  in- 
stead of  negatively,  geotropic,  although  we  know  of  no  struc- 
tural difference  between  these  and  the  branches  of  ordinary 
trees. 

§  V.  CERTAIN  MOVEMENTS  OF  PLANTS. 

257. — Under  this  head  are  to  be  considered  a  few  only  of 
the  more  important  movements  in  plants.  It  must  be  remem- 
bered that  living  protoplasm  has  everywhere,  under  proper 
conditions,  the  power  of  spontaneous  movement.  In  the 
lower  forms  of  vegetation  this  results  in  visible  movements, 
which  are  of  common  occurrence  ;  but  in  the  greater  part 
of  the  vegetable  kingdom,  while  the  protoplasm  is  doubt- 
less as  active,  the  cell- walls  which  enclose  it  are  so  rigid  that 
its  physical  activity  is  incapable  of  producing  external  move- 
ment. Thus  most  parts  of  ordinary  plants  do  not  perform 
movements  which  are  the  direct  results  of  the  physical  activ- 
ity of  the  protoplasm  ;  but  this  is  not  because  of  a  want  of 
activity  in  the  protoplasm,  but  mainly  from  the  rigidity  of 
the  walls  surrounding  it.  In  a  comparatively  small  number 
of  instances,  however,  the  structure  of  the  organs  of  even 
the  higher  plants  is  such  that  movements  directly  due  to  pro- 
toplasmic activity  are  performed.  Such  are  the  so-called 
spontaneous  movements  of  the  leaves  of  some  plants,  and 
those  dependent  upon  external  stimuli,  as  light,  heat,  me- 
chanical irritation,  etc.,  which  have  been  called  paratonic 
movements. 

258.— Spontaneous  Movements.  The  most  remarkable 
case  of  movements  apparently  not  dependent  upon  external 
agents  is  that  of  the  leaves  of  Desmodium  gyrans,  an  Indian 
plant.  The  small  lateral  leaflets  of  the  trifoliate  leaf  bend 
upon  their  slender  stalks  (petiolules)  in  such  a  way  that  their 


MOVEMENTS  OF  PLANTS.  197 

apices  describe  nearly  a  circle.  A  revolution  occupies  from 
two  to  five  minutes  if  the  temperature  is  above  22°  Cent. 
(72°  Fahr.).  This  continues,  when  the  conditions  are  other- 
wise favorable,  in  darkness  as  well  as  in  the  light.  Other  less 
noticeable  movements  of  this  nature  occur  in  many  plants — 
e.g.,  Clover,  Mimosa,  Oxalis — but  they  are  often  hidden  by  the 
more  marked  movements  due  to  other  causes.  The  active 
portion  of  the  moving  organ  (in  the  cases  cited  above,  a  por- 
tion of  the  leaf-stalk)  consists  of  a  tissue  composed  of  thin- 
walled  cells,  forming,  in  many  cases,  a  thickened  "pulvinus." 
The  cells  are  turgid  and  the  tissues  are  in  a  state  of  tension. 
When  movements  occur,  it  appears  that  the  protoplasm  in 
certain  layers  of  cells  permits  the  escape  into  the  intercellu- 
lar spaces  of  a  portion  of  the  water  of  the  vacuoles ;  it  is, 
however,  quickly  absorbed  again  and  the  cells  rendered 
thereby  turgid,  while  the  escape  of  water  takes  place  in 
contiguous  layers,  to  be  quickly  absorbed  again,  and  so  on 
regularly  around  the  axis  of  the  contracting  organ. 

259.— Movements  Dependent  upon  External  Stimuli. 
These  are  exhibited  by  many  parts  of  the  higher  plants — e.g., 
leaves  in  Mimosa  (the  Sensitive  Plant),  Cassia,  Clover, 
Oxalis,  Dionaea,  etc.,  stamens  of  many  Compositae,  of  Bar- 
berry, Portulaca,  etc.,  stigmas  of  Martynia,  Mimulus,  etc. 
In  the  Sensitive  Plant,  the  leaves,  when  touched  roughly  or 
jarred,  close  up  quickly  by  the  secondary  leaflets  moving 
upward  and  forward,  so  that  the  upper  surfaces  of  the 
pairs  are  approximated  to  each  other ;  next,  the  primary 
leaflets  bend  downward,  and  at  the  same  time  approach  each 
other,  and  finally  the  whole  leaf  bends  downward.  The 
movements  are  in  all  cases  at  the  bases  of  the  organs,  where 
tissues  are  developed  similar  to  those  in  the  spontaneously 
moving  organs  (paragraph  258).  In  the  other  cases  essen- 
tially the  same  movements  and  mechanism  are  found.  When 
the  movements  occur,  there  is  an  escape  of  the  water  of  the 
vacuoles  from  the  cells  in  one  side  of  the  organ,  and  this 
side  is,  as  a  consequence,  shortened  and  made  concave. 
After  a  time  the  water  is  reabsorbed  and  the  organ  resumes 
its  normal  position.  In  addition  to  the  mechanical  stimuli 
of  jarring,  concussion,  etc.,  greater  or  less  amounts  of  light, 


198  BOTANY. 

increase  or  decrease  of  temperature,  and  electrical  discharges, 
may  cause  movements.  Those  movements  which  are  brought 
about  by  changes  in  the  amount  of  light  constitute  what  are 
known  as  the  "  sleep"  and  "waking"  of  plants.  Thus  the 
leaves  of  the  Sensitive  Plant  close  up  in  darkness  exactly  as 
from  a  concussion,  but  they  remain  closed  until  the  reap- 
pearance of  the  light. 

260. — The  power  of  movement,  whether  spontaneous  or 
paratonic,  may  be  temporarily  suspended  by  certain  external 
conditions.  Thus,  according  to  Sachs,  transitory  rigidity 
or  immobility  takes  place  under  the  following  conditions  : 

1.  Low   Temperature.     In  Mimosa  pudica  rigidity  com- 
mences at  about  15°  Cent.  (59°  Fahr.),  in  Desmodmm  gyrans 
at  about  22°  Cent.  (72°  Fahr.). 

2.  High  Temperature.     Mimosa  slowly  becomes  rigid  at 
40°  Cent.  (104°  Fahr.),  and  very  quickly  at  50°  Cent.  (122° 
Fahr.). 

3.  Darkness.     Long  exposure   to  darkness  (twenty-four 
hours  or  more)  produces  a  rigidity  which  is  only  removed  by 
a  long  exposure  to  light. 

4.  Insufficient  Moisture.     When  the  supply  of  water  to 
the  roots  of  the  Sensitive  Plant  is  too  little,  a  partial,  and 
sometimes  almost  complete,  immobility  is  produced,  which  is 
soon  removed,  however,  by  copious  watering. 

5.  Insufficient  Supply  of  O.rygen.     In  a  vacuum,  or  in  an 
atmosphere  of  nitrogen,   hydrogen,  ammoniacal   gas,  etc., 
motile  organs  become  immobile.     On   the  other  hand,  in 
pure  oxygen  rigidity  takes  place  also. 

6.  Anmsthetics.     In  the  vapor  of  ether  or  chloroform  the 
leaves  of  the  Sensitive  Plant  become  immobile,  but  in  the 
air  they  soon  regain  their  motility. 

Mr.  Darwin's  experiments*  upon  the  leaves  of  Drosera  and 
Dionaea  are  confirmatory  of  the  foregoing  statements.  The 
sensitive  tentacles  of  the  former  and  leaf-blades  of  the  lat- 
ter were  rendered  insensible  to  the  peculiar  stimulus  of  con- 
tact with  soluble  nitrogenous  bodies  when  subjected  to  most 
of  the  above-mentioned  conditions. 


*  "  Insectivorous  Plants."     Ixmdon,  1875.     Chap.  IV.,  IX.,  and  XIII. 


MOVEMENTS  OF  PLANTS.  199 

These  facts  indicate  the  correctness  of  the  view  that  the 
movements  are  the  results  of  the  motility  of  the  protoplasm. 
261.— Movements  of  Nutation.  In  the  organs  of  many 
plants  an  inequality  of  growth  is  often  noticeable,  one  side 
growing  for  a  time  more  rapidly  than  the  other.  If  this  is 
followed  by  a  more  rapid  growth  upon  the  other  side,  and  this 
again  by  a  more  rapid  growth  upon  the  fir^t  side,  and  so  on, 
alternating  from  side  to  side,  simple  movements  of  nutation 
will  take  place,  the  apex  of  the  organ  swaying  or  oscillating 
from  side  to  side  in  one  plane.  If  the  tracts  of  unequal 
growth  pass  slowly  and  regularly  around  the  organ,  its  apex 
will  describe  a  circle  in  its  nutation. 

Of  simple  nutation  in  one  plane  many  leaves  afford  good 
examples  ;  thus  in  the  bud  the  growth  is  greatest  upon  the 
outer  or  under  side  of  each  leaf,  which,  as  a  consequence,  is 
bent  upward,  but  in  the  opening  of  the  bud  the  greater  growth 
takes  place  upon  the  upper  side.  The  greater  growth  of  the 
upper  side  of  an  organ  has  been  termed  epinasty  ;  that  of  the 
lower  side,  hyponasty.  Many  floral  leaves  exhibit  first 
hyponasty  and  afterward  epinasty,  the  first  in  the  bud  and 
the  second  in  authesis  (i.e.,  the  opening  of  the  flower). 
Many  stamens  and  styles  exhibit  nutations  of  this  nature  ; 
thus  in  Claytonia  both  sets  of  organs  are  at  first  erect,  but 
afterward  they  become  divergent  by  epinasty. 

In  many  cases,  particularly  in  leaves  and  the  parts  of 
flowers,  these  movements  of  nutation  are  controlled  by  vari- 
ous external  agents,  among  which  light  and  heat  are  the 
most  important.  To  these  are  to  be  referred  the  successive 
opening  and  closing  of  many  flowers,  and  the  diurnal  and 
nocturnal  positions  of  the  leaves  of  many  plants. 

262. — Of  the  second  class  of  nutations,  the  leaves  of  the 
onion,  and  the  ends  of  the  stems  and  the  tendrils  of  climb- 
ing plants,  furnish  good  examples.  These  rotate  through 
circles  or  spirals,  in  the  case  of  the  hop  and  honeysuckle  to 
the  left,  and  in  the  bean  and  morning-glory  to  the  right.* 


*  To  the  right,  or  from  left  to  right,  is  opposite  to  the  direction  of 
the  hands  of  a  watch  ;  to  the  left,  or  from  right  to  left,  is  in  the  direc- 
tion of  the  hands  of  a  watch. 


200  BOTANY. 

When  such  rotating  stems  come  in  contact  with  an  up- 
right object  they  continue  their  rotation,  and  in  this  way 
come  to  twine  around  it.  The  plants  mentioned  above  af- 
ford common  examples  of  twining.  In  the  case  of  tendrils 
nutations  also  occur  ;  but  after  coming  in  contact  with  any 
object  there  is  a  very  unequal  growth  of  the  two  sides,  that 
in  contact  with  the  object  growing  very  slowly,  as  compared 
with  the  rapidity  of  growth  of  the  outer  side.  Thus  De 
Vries  found  that  in  the  tendrils  of  the  pumpkin  twined 
around  an  object  1.2  mm.  in  diameter  the  ratio  of  the 
growth  of  the  inner  side  to  that  of  the  outer  was  as  1  to  14. 
This  inequality  of  growth  is  due  to  a  retardation  of  growth 
upon  the  inner  side  and  an  acceleration  upon  the  outer. '  In 
some  cases  there  appears  to  be  an  actual  contraction  of  the 
inner  side. 

263.— Movements  of  Torsion.  In  many  cases  in  the 
higher  plants  the  stems  or  other  organs  become  twisted  upon 
their  axes.  Even  in  the  lower  plants  this  is  not  uncommon — 
e.g.,  in  Nitella,  the  pedicels  of  mosses,  etc.  This  twisting 
appears  in  many  cases  to  be  due  to  a  peculiar  inequality  in 
the  growth  of  the  tissues.  Thus  if  the  outer  layers  of  cells 
grow  in  length  more  rapidly  than  the  inner  ones,  the  stem 
will  become  twisted  upon  its  axis,  and  the  greater  the  ine- 
quality in  growth  of  the  inner  and  outer  layers,  the  greater 
the  torsion.  In  some  cases  torsion  arises  in  a  much  simpler 
way,  by  the  twisting  due  to  the  unequal  distribution  of  the 
weight  of  certain  organs,  as  in  some  prostrate  plants,  where 
the  weight  of  the  leaves  and  the  advancing  and  obliquely 
ascending  growing  extremity  of  the  stem  produce  torsions 
which  become  permanent  by  the  hardening  of  the  tissues. 
Likewise  torsions  may  arise  on  account  of  the  heliotropism  or 
geotropism  of  an  organ  itself,  or  of  organs  connected  with  it. 

It  may  be  in  place  here  to  direct  attention  to  the  fact  that  inequali- 
ties in  the  growth  of  the  tissues  of  plants  are  of  common  occurrence. 
They  are,  however,  for  the  most  part  of  such  a  nature  as  to  prevent 
torsions  of  the  stem,  giving  it,  on  the  contrary,  a  rigidity  which  en- 
ables it  to  stand  erect.  If  the  pith  of  a  growing  stem  of  a  Dicotyledon 
be  isolated  from  the  surrounding  tissues,  the  former  elongates,  while 
the  latter  contracts,  showing  that  the  pith  has  grown  more  rapidly  in 


MO  VUMENTS  OF  PLANTS.  201 

length  than  the  other  tissues.  Thus  in  a  young  internode  of  the  Moun- 
tain Ash,  60  min.  long,  the  pith,  when  isolated,  elongated  3  mm.,  while 
the  surrounding  parts  shortened  1  mm.  Close  examination  of  the  tissues 
surrounding  the  pith  shows  that  they  also  have  developed  unequal- 
ly.  Sachs  expresses  this  inequality  by  the  formula,  E  <  C  <  X  <  P, 
which  indicates  that  the  epidermis  is  shorter  than  the  cortex,  the 
cortex  shorter  than  the  xylem,  and  the  xylem  shorter  than  the  pith.  It 
is  at  once  evident  that  in  such  a  condition  of  things  the  epidermis  is 
elongated  by  the  other  tissues  ;  the  cortex  is  shortened,  on  the  one 
hand,  by  the  epidermis,  and  elongated  on  the  other  by  the  xylem  and 
pith  ;  the  xylem  is  shortened  by  the  cortex  and  epidermis,  and  elon- 
gated by  the  pith  ;  while  the  pith  is  shortened  by  the  three  surround- 
ing tissues.  There  is  thus  a  considerable  tension  in  the  several  tissues, 
and  upon  this  condition  it  may  be  remarked  : 

1st.  That  it  produces  a  rigidity  of  the  steins  or  other  organs  in  which 
it  occurs. 

3d.  That  it  tends  to  prevent  ordinary  torsion ;  for  the  twisting  of 
such  a  stem  must  elongate  still  more  the  already  elongated  tissues, 
while  contracting  the  shortened  ones ;  on  the  other  hand,  there  is  some 
tendency  to  an  internal  torsion. 

3d.  That  the  exact  length  of  a  stem  is  dependent  upon  a  balancing 
of  the  tensions  of  its  tissues. 

There  are  in  many  cases  tensions  whose  directions  lie  at  right  angles 
to  the  foregoing.  Thus  in  the  trees  of  the  colder  climates  the  growth 
of  new  tissues  from  the  cambium  layer  produces  an  outward  pressure 
upon  the  bark,  and  an  equal  inward  pressure  upon  the  wood.  Even  in 
herbaceous  plants  similar  tensions  are  often  to  be  observed,  the  epider- 
mis being  laterally  distended  by  the  enclosed  tissues.  Tensions  in  this  . 
direction  have  been  denominated  transverse  tensions,  to  distinguish 
them  from  the  others,  which  may  be  called  longitudinal  tensions.* 

*  For  a  full  discussion  of  tensions  the  student  is  referred  to  larger 
works,  such  as  Sachs'  "Lehrbuch,"  and  his  "  Experimental-Physi- 
ologic." 

The  whole  subject  of  the  movements  of  plants,  including  heliotro- 
pism  and  geotropism,  is  fully  treated  by  Mr.  Darwin  in  his  recent 
work  "  The  Power  of  Movement  in  Plants,"  New  York,  1881. 


PART  II. 

SPECIAL  ANATOMY   AND   PHYSIOLOGY   OF    PLANTS, 
AND  OUTLINES  OF   THEIR   CLASSIFICATION. 


CHAPTER    XIII. 
CLASSIFICATION. 

264. — In  order  to  obtain  a  definite  knowledge  of  the  com- 
parative structure  of  plants,  it  is  necessary  here  to  take  up 
in  order  the  different  groups,  and  to  study  with  some  care 
the  more  important  modifications  and  differences  noticeable 
in  the  plant-body.  This  study,  so  taken  up,  is  intimately 
connected  with  the  classification  of  plants  ;  the  differences 
and  modifications  of  structure  which  we  study  in  order  to 
gain  a  better  knowledge  of  plants  as  a  whole,  are  the  very 
ones  which  serve  to  separate  the  vegetable  kingdom  into 
larger  or  smaller  groups.  This  part  (Part  II.)  of  this  trea- 
tise will,  therefore,  include  the  outlines  of  the  Classification 
of  Plants,  as  well  as  a  discussion  of  Special  Morphology. 

265. — (1.)  In  the  classification  of  1  iving  objects  they  "are 
arranged  according  to  the  totality  of  their  morphological  re- 
semblances, and  the  features  which  are  taken  as  the  marks 
of  groups  are  those  which  have  been  ascertained  by  observa- 
tion to  be  the  indications  of  many  likenesses  or  unlikenesses."* 
Such  an  arrangement  is  "  a  statement  of  the  marks  of  sim- 
ilarity of  organization,  and  of  the  kinds  of  structure  which, 
as  a  matter  of  experience,  are  universally  found  associated 
together." 

*  T.  H.  Huxley  in  the  article  "Biology,"  in  "  Encyclopedia  Britan- 
nica,"  ninth  edition,  Vol.  Ill  ,  j>.  683. 


CLASSIFICATION.  203 

266.— (2.)  Every  natural  classification  takes  into  consider- 
ation not  only  the  adult  characters,  but  also  those  of  the 
embryonic  life  of  its  objects.  It  is  not  enough  to  know  the 
differences  and  resemblances  between  two  plants  in  their 
adult  state  ;  we  must  also  know  whether  they  differed  or  not 
in  their  modes  of  reaching  that  state.  In  other  words,  in 
order  to  determine  the  degree  of  relationship  existing  be- 
tween two  or  more  plants,  all  the  characters  of  each  plant, 
as  presented  in  its  whole  life,  must  be  taken  into  the  ac- 
count. By  ignoring  this  important  law  great  confusion  has 
arisen,  especially  in  the  lower  groups  of  plants. 

267. — (3.)  There  is  still  another  factor  which  should 
enter  into  classification.  Every  classification  should  show 
real  relationship,  not  similarity  alone ;  it  should  bring  to- 
gether not  those  which  simply  show  present  coincidences, 
but  those  in  which  similarity  of  form  indicates  similarity 
of  origin  ;  in  addition  to  structural  relationship,  it  should 
show  genetic  relationship.  This  can  be  accomplished  only 
by  a  study  of  the  genealogy  of  plants,  a  subject  surrounded 
by  many  difficulties.  In  but  few  cases  can  we  trace  an 
ancestral  line,  and  yet  it  is  desirable  that  we  should  use  the 
facts  we  have,  as  by  so  doing  we  shall  be  the  more  likely  to 
discover  others. 

(a)  It  is  a  mistaken  notion  that  living  things  can  be  grouped  natu- 
rally by  taking  into  consideration  only  one,  or  even  two  or  three  char- 
acters. Botany  and  zoology  are  full  of  the  debris  of  attempts  at  classi- 
fications upon  single  characters,  and  in  every  case  such  classifications 
have  proved  a  hindrance  to  knowledge.  The  division  of  the  vegetable 
kingdom  into  Flowering  and  Flowerless  Plants,  by  Ray,*  in  1703,  is  an 
illustration  of  one  based  upon  a  single  character.  The  influence  of 
this  classification,  which  is  even  yet  much  followed,  has  been  injurious. 
It  has  kept  alive  the  notion  that  the  so-cnlleii  Flowerless  plants  are 
quite  different  as  to  their  reproductive  organs  from  the  Flowering  ones; 
it  fixed  an  imaginary  gulf  between  groups  of  plants,  some  at  least  of 
which  are  in  nature  placed  side  by  side.  Endlicher'sf  two  great 
groups,  Cormophy ta  and  Thallophyta,  are  likewise  based  upon  a  single 
character,  and  are,  as  a  consequence,  misleading.  The  Thallophytes  are 

*  John  Ray  :  "  Methodus  Plantarum  emendata  et  aucta." 
f  Stephen  Endlicher:  "Genera  Plantarum  secundum  Onlines  Natu 
rales  disposita."     1830-40. 


204  BOTANY. 

not  all  thallus  plants,  nor  are  all  the  thallus  plants  found  in  the  Thal- 
lophyta  ;  on  the  other  haud,  the  Cormophytes  are  not  all  plants  with 
trunks  or  stems. 

(6)  We  often,  however,  retain  in  our  present  classification  some  of 
the  groups  founded  originally  in  this  erroneous  way,  and  even  some- 
times retain  their  old  names.  For  example,  the  group  Phanerogamia 
includes  now  the  same  plants  it  did  when  its  exceedingly  inapplicable 
name  (Phanerogamia,  from  QavepoS,  open  to  sight,  and  ya^oS,  marriage) 
was  applied  to  it  ;  but  it  now  rests  upon  a  more  scientific  basis.  The 
name  is  now  unmeaning,  and  refers  to  no  character  or  set  of  characters 
now  used  to  designate  the  group  ;  and,  more  than  this,  its  etymological 
signification  is  actually  directly  opposite  to  the  facts  as  now  known. 
The  term  Cryptogamia  (/cpiwrof,  hidden,  and  ya.fj.os,  marriage)  no  longer 
exists  in  a  scientific  sense,  as  it  is  no  longer  the  name  of  a  group  of 
plants ;  not  only  has  the  term  now  no  meaning  (for  the  plants  it  refers 
to  have  a  fertilization  which  is  far  less  "  hidden  "  than  in  the  so-called 
Phanerogams),  but  the  plants  it  formerly  designated  by  a  negative 
character  are  now  known  by  positive  characters  to  belong  to  several 
groups.  We  may  still  use  the  word  Cryptogam  in  speaking  of  the 
members  of  certain  groups  of  plants,  just  as  in  zoology  we  frequently 
make  use  of  the  word  Invertebrate  ;  but  in  neither  case  are  the  terms 
the  names  of  natural  groups,  or  of  natural  assemblages  of  groups.  It 
is  convenient  to  retain  them  as  popular  names  of  certain  artificial  as- 
semblages of  groups. 

(c)  The  term  Thallophyta  is  to  be  placed  in  the  same  category.     It  is 
still  used  to  designate  a  great  assemblage  of  the  lower  plants,  but  the 
original  meaning  of  the  term  is  lost,  and  the  limits  of  the  group  to 
which  it  was  applied  have  been  somewhat  changed,  while  the  plants 
composing  it  have  undergone  an  entirely  new  distribution  into  new 
groups.     Nevertheless,  it  is  convenient  to  retain  the  term,  although  in 
this,  as  in  the  previous  cases,  care  must  be  taken  not  to  suppose  that 
when  used  it  designates  more  than  an  artificial  assemblage  of  natural 
groups  of  plants. 

(d)  The  importance  of  the  study  of  the  individual  development  of 
plants  can  hardly  be  overestimated.     What  Embryology  has  done  for 
zoological,  it  doubtless  can  do  for  botanical  classification.     It  is  already 
bearing  fruit  ;  the  recent  advances  in  the  classification  of  the  algae  and 
fungi  are  due  to  a  study  of  the  whole  life  of  the  individual.     In  the 
fungi  the  long  list  of  spurious  families  and  genera,  and  the  yet  longer 
one  of  spurious  species,  bear  witness  against  the  system  of  classification 
under  which  they  came  into  existence. 

(e)  There  is  another  reason  for  studying  closely  the  life-history  of  the 
individual,  which  is  that  it  throws  some  light  upon  the  difficult  ques- 
tions relating  to  the  ancestry  of  plants.     The  life-history  of  the  indi- 
vidual appears  to  bear  much  resemblance  to  the  life-history  of  the 
species  ;  and  while  no  doubt  it  would  be  unsafe  in  any  particular  case 


CLAS8IFICA  TION. 


205 


to  assume  that  the  specific  development  had  followed  lines  parallel  to 
those  of  the  individual,  yet  the  latter  may  always  serve  to  point  out  the 
probable  course  of  the  former. 

268. — Applying  the  preceding  principles,  so  far  as  possi- 
ble, we  find  that  the  vegetable  kingdom  may  be  quite  readily 
separated  into  six -principal  Divisions,  which,  although  by  no 
means  distinct,  are  capable  of  being  quite  clearly  character- 
ized. To  these  must  be  added  a  seventh,  composed  mainly 
of  unclassified  and  poorly  understood  forms.  These  seven 
Divisions,  beginning  with  the  lowest,  are,  (1)  Protophyta, 
(2)  Zygosporeae,  (3)  Oosporeae,  (4)  Carposporeae,  (5)  Bryo- 
phyta,  (6)  Pteridophyta,  (7)  Phanerogamia. 

Their  relation  to  the  old  groups  Cryptogamia,  Thallophy- 
ta,  etc.,  may  be  seen  from  the  following  tabular  comparison  : 


Ray,  1703;  Linnaeus,  1735. 


Flowerless  (Ray), 


II. 

De  Candolle, 
1813. 


III. 

Endlicher, 
1836-40. 


IV. 


Cryptogamia 

nseus). 


(Lin- 


Flowering  (Ray), 
Phanerogamia(Linn.) 


.  .  f  1.  Protophyta. 


C.ll.l.r    ThallopV.,     |  £f ^ 

1  lants'          I  4.  Carposporeae. 

[ f  5.  Bryophyta. 

Vase  u  1  a  r /Cormophyta.  J  G'  Pteridophyta. 

Plant8'       1 (.7.  Phanerogamia. 


The  arrangement  in  the  fourth  column,  which  will  be  fol- 
lowed in  this  book,  is  essentially  that  of  Sachs,  with  some 
modifications,  which  will  be  pointed  out  hereafter. 

It  is  only  necessary  in  this  place  to  say  that  the  classification  here 
given  does  not  recognize  the  old  groups  Algce  and  Fungi.  The  terms 
are,  however,  quite  useful,  if  properly  used  and  understood,  and  con- 
sequently they  will  be  retained  when  general  reference  is  made  to  the 
chlorophyll- bearing  and  the  chlorophyll-free  Thallophytes.  By  the 
term  alga  must  be  understood  a  Thallophyte  which  contains  chloro- 
phyll ;  and  by  fungus  one  which  is  saprophytic  or  parasitic  in  habit, 
and  which  is,  as  a  consequence,  destitute  of  chlorophyll.  The  terms 
liave  thus,  as  here  used,  a  physiological  meaning  only,  and  not  a  class- 
ificatory  one. 


CHAPTER  XIV. 

THE    PROTOPHYTA. 

269. — The  Protophytes  are  the  lowest  and  simplest  plants. 
In  many  cases  they  are  exceedingly  minute,  requiring  the 
highest  powers  of  the  microscope  for  their  study.  For  the 
most  part  the  cells  are  poorly  developed  ;  the  protoplasm 
is  frequently  destitute  of  granular  contents  ;  the  nucleus  is 
wanting  in  many  cases,  and  not  infrequently  there  is  either 
no  cell-wall,  or  only  a  poorly  developed  one.  The  cells  in 
all  cases  have  little  or  no  coherence,  and  even  when  they  are 
united  into  loose  masses,  each  cell  retains  nearly  as  much 
independence  as  in  the  unicellular  forms.  The  differentia- 
tion of  cell-form  is  very  slight,  even  in  those  cases  where 
there  is  the  greatest  coherence  of  cells,  and  yet  in  some  or- 
ders certain  cells  of  the  filaments  are  uniformly  larger  than 
the  others,  as  the  "  heterocysts  "  of  Nostoc,  and  the  "  basal 
cells"  of  the  filaments  of  Rivularia. 

270. — No  sexual  organs  are  known,  and  whether  the  sex- 
ual act  occurs  or  not  is  somewhat  doubtful.  As,  however. 
we  must  not  expect  to  find  well-developed  organs  or  as 
distinct  a  sexual  act  in  these  simple  organisms  as  in  more 
complex  ones,  it  is  possible  that  both  exist  in  the  group, 
but  have  hitherto  been  overlooked  or  misunderstood. 

Their  most  common  mode  of  reproduction  is  by  fission, 
and  in  only  a  few  cases  by  internal  cell-division. 

271. — The  lowest  Protophytes  are  destitute  of  chlorophyll, 
or  any  other  coloring-matter,  and  in  those  orders  in  which 
chlorophyll  occurs  it  is  usually  associated  with  a  blue  or  red 
pigment. 

Many  Protophytes  exist  in  masses  of  a  considerable  size, 
composed  of  large  numbers  of  individuals  imbedded  in  a 


MYXOM7CETES.  20? 

gelatinous  matter,  which  appears  to  be  formed  by  a  partial 
degradation  of  the  walls  of  the  cells.  They  are  mostly 
aquatic  ;  and  the  species  which  are  terrestrial  live  in  damp 
and  generally  shaded  places. 

§  I.   CLASS  MYXOMYCETES.     THE  SLIME  MOULDS. 

272. — In  this  class  is  included  a  large  group  of  remark- 
able organisms,  which  differ  in  many  respects  from  all  other 
vegetable  structures.  In  many  of  their  characters,  as  in 
having  no  cell-wall  during  the  period  of  their  active  growth, 
in  being  destitute  of  a  nucleus,  in  their  mode  of  nutrition, 
and  in  the  motility  of  their  naked  protoplasm,  they  resemble 
certain  Monera  among  the  Protozoa ;  *  while,  on  the  other 
hand,  they  have  a  close  external  resemblance  to  certain 
higher  fungi  (puff-balls  and  their  allies). 

273. — It  is  difficult  to  give  the  Myxomycetes  a  satisfac- 
tory place  in  a  system  of  classification.  They  have  no  struc- 
tural affinities  with  plants  higher  than  they  are,  nor  with 
any  lower  ;  they  stand  alone,  and  appear  to  belong  to  a  dif- 
ferent genetic  line.  So,  although  taken  up  here,  they  must 
not  be  regarded  as  on  that  account  the  lowest  or  the  first  of 
the  Protophytes. 

274. — All  members  of  this  class  agree  in  being  composed 
during  the  vegetative  portion  of  their  existence  of  naked 
masses  of  protoplasm  (Fig.  140),  which  are  yellow,  brown, 
purple,  etc.,  but  never  green.  These  plasmodia,  as  they  are 
called,  are,  during  the  period  of  their  active  growth,  endowed 

*  There  are  fewer  reasons  now  than  formerly  against  regarding  these 
as  near  relatives  of  the  Monera.  We  no  longer  imagine  an  absolute 
line  of  separation  between  the  lower  portions  of  the  great  domain  of 
life,  and  hence  may  now  admit  relationships  which  formerly  were  in- 
admissible. It  is  by  no  means  an  improbable  hypothesis  that  in  the 
Myxomycetes  we  have  the  terrestrial  phase  and  in  the  Monera  the 
aquatic  phase  of  a  common  group  of  organisms.  The  Myxomycetes  are 
not  Monera,  but  they  are  Moneran  in  their  structure,  and  probably  also 
in  their  affinities.  All  the  differences  between  the  Myxomycetes  and  a 
Moner  like  Protomyxa,  for  example,  are  probably  referable  to  the 
terrestrial  habit  of  the  former  as  contrasted  with  the  aquatic  habit  of 
the  latter. 


208 


BOTANY. 


with  a  remarkable  motility,  enabling  them  not  only  to 
change  their  form,  but  their  place  also.  When  the  proto- 
plasm passes  into  a  condition  of  rest,  it  forms  itself  into 
small  rounded  masses,  each  of  which  secretes  a  covering  of 
cellulose  about  itself.  This  resting  condition  may  be  brought 
about  in  two  ways  :  first,  through  unfavorable  conditions, 
as  the  absence  of  the  requisite  amount  of  moisture  ;  in  such 


Fig.  140.— Plaamodium  of  Physarum  leucopus  (Didymium  leucojnis  of  Link),    st, 
the  more  granular  cuntiul  part  of  the  threads.     X  350. — After  Sachs. 

cas.e  the  masses  formed  are  larger,  and  irregular  in  size,  and 
constitute  the  so-called  sderotium  stage ;  upon  the  return  of 
the  proper  conditions  the  sclerotia  return  to  the  soft  and 
motile  condition  of  the  original  plasmodium  ;  the  second 
mode  of  formation  of  the  resting  stage  takes  place  only 
when  the  plasmodium  has  apparently  concluded  its  period 
of  vegetation  ;  the  protoplasm  becomes  heaped  up  in  a  com- 
pact or  even  elevated  mass,  which  then  separates  internally 


MYXOVYCETES. 


209 


into  a  large  number  of  minute  rounded  bodies,  the  spores, 
each  of  which  is  provided  with  a  cell-wall.  This  latter  is 
called  the  spore-bearing  stage,  or  simply  the  fructification  of 
the  organisms. 

275. — When  placed  under  proper  conditions  of  moisture 


Fig.  141. — Fuligo  variant  (jOlthalium  septicum  of  Pr.).  a  spore;  b,  c,  spore-case 
rupturing  and  permitting  the  protoplasmic  contents  to  escape;  grounded  mass  of 
naked  protoplasm  escaped  from  the  spore-case;  e,  f,  ciliated  swarm-cpore  or 
zoospore  stage;  g,  h,  i,  k,  I,  amoeba  stage;  m,  young  plusinodium. — After  Prantl. 

and  temperature,  the  spores  burst  their  walls,  and  the  im- 
prisoned protoplasm  in  each  escapes  and  soon  becomes  a 
motile,  nucleated  mass,  provided  with 
a  cilium,  or  having  an  amoeboid  form  ; 
in  this  stage  (called  the  swarm-spore) 
it  repeatedly  divides  by  simple  fission 
(Fig.  142).  After  a  day  or  two,  the 
swarm-spores,  now  destitute  of  cilia, 
begin  the  reverse  process  of  coales- 
cing, two  or  more  of  them  fusing  into 
a  common  mass;  the  process  may 
continue  until  a  new  plasmodium  is  x  390.— After  DC  Bary. 
formed,  differing  from  the  first  one  mentioned  only  in  size 
(Fig.  141,  a  to  m,  and  Fig.  143). 

276. — The  classification  of  the  Myxomycetes  is  mainly 
based  upon  the  fructification,  which  usually  consists  of  a 


-no 


BOTANY. 


sporangium,  which  may  be  distinct  (Fig.  144,  B],  or  it  may 
be  a  flattish,  cake-like  mass,  the  so-called  cethalium,  directly 
derived  from  the  plasniodium.  lu  most  cases  the  spore- 
bearing  masses  contain  internally,  besides  the  spores,  a 
structure  called  the  Capillitium,  consist- 
ing of  thin-walled,  spirally  thickened,  or 
otherwise  marked  tubes  variously  disposed 
(Fig.  144,  C,  cp).  In  some  cases,  where 
there  is  a  distinct  sporangium,  the  pedi- 
cel of  the  latter  is  continued  into  it  as  a 
central  colnmn  ;  this  is  known  as  the  Col- 
umella  ;  it  may  send  out  branches  which 
support  the  walls  of  the  sporangium. 


143.  —  Swarni- 
uporesof  Clioinli'imlfr- 
ma  diffonne  (Didy- 
mitim  LiAertian.um  of 
De  Bary)  coalescing  or 
conjugating,  x 
'  "  ur  Cie 


After 


enkowski. 


(a)  The  latest  classification  of  the  Myxomycetes 
is  by  Rostafinski.*  He  distinguishes  seven  or- 
ders, as  follows  : 

Order  I.  Protodermese.  Sporangia  simple,  of  regular  shape,  not 
possessed  of  a  capillitium,  with  violet  spores. 

Order  II.  Calcarese.  Sporangia  simple  or  compound,  often  pro- 
vided with  a  columella,  spores  violet  or  violet  brown  ;  whole  fructifica- 
tion, with  more  or  less  de- 
posits of  carbonate  of  lime. 

This  includes  many  com- 
mon species,  under  the 
genera  Pliyaazum,  Fuligo, 
Diilyiitiutn,  Xpnmaria,  etc. 

Order  III.  Amauro- 
chaeteae.  Single  sporan- 
gium or  asthalium,  with- 
out lime  ;  spores,  capilli- 
tium, and  columella  almost 
always  uniformly  black,  or 
brownish-violet  colored. 

In  this  order  the  genus 
Stemonitis  furnishes  the 
most  common  species. 

Order  IV.  Anemeee. 
Sporangium  or  aethalium 
without  capillitium  or  lime;  columella  not  evident,  wall  of  sporan- 

*  "Monografia  Sluzovvce."  Dr.  Joseph  Rostafinski,  1875.  An  Eng- 
lish translation  of  so  much  as  pertains  to  British  species  may  be  found 
in  "The  Myxomycetes  of  Great  Britain,"  by  M.  C.  Cooke,  1877.  In  a 


Fig.  144. — Fructification  of  Arcijiia  incarnate 
(A.  adiiata  of  Htfki.).    Ji.  young  sporangium;  C, 
capillit: 


ruptured;   c p, 


mature  nporangiu          .  .... 

p,  wall  of  sporuugium.    X  20.— After  Sachs. 


litium  ; 


SCHIZOMYCETES.  211 

gium  without  net-like  thickenings,  now  and  then  symmetrically  per. 
f orated. 

Licea  and  Tubulina  are  genera  of  this  order  of  which  we  have 
species. 

Order  V.  Heterodermese.  Sporangia  without  capillitium,  colu- 
mella,  or  lime  ;  wall  of  sporangium  delicate,  when  mature  at  least  partly 
cracked,  exposing  the  net-like  flat  thickenings  of  the  inner  side  of  wall  ; 
spores  and  thickenings  of  the  inner  wall  in  one  and  the  same  sporan- 
gium usually  of  uniform  color. 

Dictydium  and  Crtbraria  are  our  common  genera. 

Order  VI.  Columelliferse.  Spores,  capillitium,  and  columella 
uniformly  bright-colored,  without  lime  ;  capillitium  of  very  thin-sided 
tubes,  without  thickenings,  combined  into  a  thickly  intricate  but  loose- 
hanging  net. 

Represented  by  the  genus  J^^^nria. 

Order  VII.  Calonemese.  Walls  of  sporangia,  spores,  and  capillitium 
usually  uniformly  colored  in  the  same  sporangium.  Color  variable 
from  yellow  to  brownish  or  chestnut ;  more  rarely  olive  green  or  gray- 
ish white  ;  capillitium  usually  strongly  developed  ;  threads  simple,  or 
combined  into  a  net,  either  entirely  free  or  grown  to  certain  places  of 
the  wall  of  the  sporangium  ;  walls  of  the  threads  very  rarely  smooth, 
usually  provided  externally  with  protruding  thickenings,  either  spiral- 
shaped  or  under  the  form  of  numerous  spines,  warts,  or  transverse 
rings  ;  without  fixed  columella  ;  exceptionally  containing  lime,  exclu- 
sively on  the  walls  of  the  sporangia;  now  and  then  aethalia  covered 
with  a  stout  double  cortex  of  colored  cells, 

Arcyri&-Biud  TVt'cAjg  are  our  common  genera. 

(&)  Specimens  of  the  Slime  Moulds  may  be  obtained  for  study  by  ex- 
amining the  surfaces  of  decayed  logs,  and  the  bark-covered  ground  in 
tan-yards.  They  may  frequently  be  found  on  decaying  leaves,  and 
occasionally  on  the  grass  and  mosses  near  decaying  vegetable  matter. 

§  II.  CLASS  SCHIZOMYCETES. 

277. — These  are  minute  unicellular  Protophytes,  which 
reproduce  by  simple  transverse  fission.  The  cells  are  gener- 
ally somewhat  elongated,  often  much  so,  although  in  one 
family  they  are  spherical  ;  they  are  sometimes  provided  with 
cilia,  by  means  of  which  they  move  rapidly  through  the 

paper  entitled  "  The  Myxomycetes  of  the  United  States,"  published  in 
the  Annals  of  the  Lyceum  of  Natural  History  of  New  York,  Vol.  XT., 
1877,  the  same  author  enumerates  our  species  according  to  Rostafinski's 
arrangement,  and  gives  a  copious  list  of  synonyms. 


212  BOTANY. 

water.  They  occur  in  solutions  of  organic  matter  in  im- 
mense numbers,  and  are  said  even  to  appear  in  solutions  of 
inorganic  salts  under  proper  conditions.* 

278.— Order  Bacteriacese.  This  includes  the  organisms 
known  as  Bacteria,  and  which  are  present  in  fermenting  and 
putrefying  matter  ;  they  also  occur  in  the  blood  and  the  air- 
passages  of  diseased  animals,  and  if  not  the  cause,  they  appear 
to  be  common  accompaniments  of  many  kinds  of  disease. 
Cohn,f  who  has  recently  studied  them,  defines  Bacteria  as 
"  chlorophyll-less  cells  of  spherical,  oblong,  or  cylindrical 
form,  sometimes  twisted  or  bent,  which  multiply  themselves 
exclusively  by  transverse  division,  and  occur  either  isolated 
or  in  cell-families."  They  elongate  to  double  their  normal 
length  and  then  become  constricted  in  the  middle  so  as  to 
form  two  cells  ;  branching  never  occurs.  In  the  unicellular 
Bacteria  the  cells  resulting  from  division  separate  at  once, 
while  in  the  filamentous  forms  they  remain  in  connection, 
forming  strings  or  threads.  Unicellular  Bacteria  sometimes 
form  a  jelly-like  mass  by  the  swelling  up  of  their  cell  mem- 
branes ;  this  is  the  Zooglcea  stage  of  Colin  ;  it  does  not  occur 
in  the  filamentous  species.  "  Bacteria  frequently  form  an 
oily  stratum  near  the  surface  of  a  liquid  (attracted  by  oxy- 
gen) ;"  to  this  condition  Pasteur  erroneously  applied  the 
name  "  mucor,"  in  his  reports  upon  his  experiments  on  spon- 
taneous generation.  Sometimes  they  form  a  toughish  pelli- 
cle on  the  surface  of  the  liquid,  in  which  the  Bacteria  are 
closely  packed  ;  this  is  the  "  Mycoderma  "  of  Pasteur's  re- 
ports. Lastly,  when  they  have  exhausted  the  nutriment 
from  the  liquid,  they  form  a  pulverulent  precipitate,  which 
may  be  regarded  as  a  resting  state. 

"Most  Bacteria  present  a  motile  and  a  motionless  condi- 
tion ;  the  former  is  connected  with  the  presence  of  oxygen." 

*  See  Bastian's  "  Beginnings  of  Life,"  Vol.  II.,  Appendix. 

f  "  Researches  on  Bacteria  "  (Untereuch.  iiber  Bacterien)  in  "  Beitrage 
zur  Biologie  der  Pflanzen,"  Breslau,  1872.  See  a  resume  of  this  paper 
in  Quarterly  J^urnil  of  Microscopical  Science,  1873,  p.  156.  See  also 
English  accounts  of  further  researches  by  (John,  1875,  1876 ;  in  the 
journal  just  cited,  1876,  p.  259,  and  1H77.  p.  81.  Consult  ••  Tin-  Bao- 
teria,"by  Dr.  A.  Magnin  ;  translated  by  Dr.  Stcrnberg.  Boston,  1880. 


8CHIZOMYCETE8. 


213 


(a)  Colin  separates  Bacteria  into  four  tribes,  as  follows  : 

(1)  Sphcerobacteria,  with  spherical  cells.  The  only  genus  is  Micrococ- 
cus.    The  species  M.  crepusculum,  M.  candidus,  and  M.  urece  produce 
certain  kinds  of  fermentation  ;  the  color-producing  species  are  M.  pro- 
digiosus  (a,  Fig.  145),  which  causes  the  blood-like  patches  on  bread, 
flour,  paste,  etc.,  M.  luteits,  M.  aurantiacus,  M.chloriiiu",  M.cyaneus, 
and  M.  violaceus  ;  those  producing  or  accompanying  diseases  are  M. 
vaccince,  M.  diphthericus,   M.  septicus,  and  M.  bombycis.      This  latter 
group  is  of  great  importance,  but  it  is  one  the  investigation  of  which 
presents  unusual  difficulties.    Oth- 
er  species   than  those  named   are 

supposed  to  exist. 

(2)  Microbacteria,     with     very 
small  cylindrical  cells.     The  only 
genus  is  Bacterium.     The  species 
are,  B.   Termo  (b,  Fig.  145),  the 
common    agent    of    putrefaction  ; 
B.  lineola  (c,   Fig.    145),  a  larger 
species     found     in     brooks     and 
ponds  ;  B.  xanthinum  and  B.  syn- 
cyanum,  which  are  color-produc- 
ing ;   and  B.  ceruginosum,    which 
is  found  in  blue-green  pus. 

(3)  Dcsmobacteria,  with  filiform 
cells.     There  are  two  genera,  Ba- 
cillus, with  the  filament  straight, 
and  Vibrio,  with  the  filament  curv- 
ed or  undulated.    Of  the  first  there 
are  three  species,  viz.:  B.  subtilis, 
which  is  the  butyric  ferment ;  B. 
ulna  (d,  Fig.  145),  much  like  the 
preceding,    but    larger ;    and    B. 
anthraci*,  which   is  the   cause  or 
accompaniment 

known  as  "  the  blood  "  and  "ma- 
lignant pustule."  Vibrio  has  two 
species,  viz. :  V.  Rugula  (e,  Fig.  145),  whose  cells  are  thick  and  rather 
short  ;  and  V.  serpens,  whose  cells  are  of  smaller  diameter,  but  <-i 
greater  length  than  the  preceding. 

(4)  Spirobactein,  with  spirally  twisted  cells.     There  are  two  genera, 
Hpirochmte,  with  a  much  twisted  spiral  ;  and  Spirillum,  with  a  less 
twisted  spiral.     Of  the  first  the  single  species  is  Sp.  plicati'is  (/,  Fijr. 
145),  and  of  the  second,  Sp.  tenue,    Sp.  andula  and  Sp.  volutans  (g, 
Fig   145),  the  latter  a  gigantic  species,  with  a  flagellum  at  each  end 
of  the  spiral. 

(b)  Bacteria  may  be  readily  procured  for  study  by  infusing  a  pinch 


Fig.  145.    a,  Micrococo/9  prodigiously 
.  Mimus  prodigiosux   of   Ehvonberg) :    b. 
of     the     diseases    Boefcrtwm  7'emo,  zoo^ltva  stage  ;  e,  .ffoc- 
3    terium  lineola;  d.  BaciUw  ulna;  e,  Vi 
brio  Rugula ;  f,  tf/>i n/rhift/ •  /i.'iratilis ;  ff, 
Spirillum  volutans.     x  650.— After  Cohii. 


214  BOTANY. 

of  cut  Lay  or  any  other  similar  vegetable  substance  in  warm  water  for 
an  hour,  and  then  filtering;  the  filtrate  will,  if  kept  at  the  ordinary 
temperature  of  a  room  (20°  C.),  and  allowed  free  access  of  air,  become 
turbid  with  Bacteria  in  the  course  of  one  or  two  days. 

(e)  By  adding  a  drop  of  the  hay  infusion  to  Pasteur's  solution,*  made 
without  sugar,  the  previously  clear  liquid  is  soon  made  turbid  by  the 
rapid  increase  of  Bacteria.f 

279.  —  Allied  to  the  Scliizomycetes  are  the  species  of  Sac- 
charomyces  which  produce  fermentation  in  sugar  solutions. 
The  type  of  the  genus  is  Saccharomyces  cere  vis  ice,  the  yeast 
plant  (Fig.  146).  It  presents  two  conditions  :  in  the  first  it 
is  in  the  form  of  transparent  round  or  oval  cells,  averaging 
.008  mm.  (.0003  inch)  in  diameter;  these  reproduce  by  bud- 
ding (a  modification  of  fission),  a  small  daughter-cell  being 
formed  by  the  side  of  the 
mother-cell,  and  sooner  or  later 
separating  from  it  (Fig.  146,  a, 
^)*  ^ie  °tner  form  consists  of 
larger  cells,  which,  by  a  division 
of  their  protoplasm,  form  four 
new  cells  within  the  parent-cell 
(Fig.l46,C,d).  This  is  probably 


from  "  bottom  yeast,"  50  hours  after  no  more  than  the    Ordinary 
fiowing  in  beer-wort;  6.  row  of  oval  •      •  T    •   • 

cells  from  "  top  yeast  ;"  c,  "  bottom  C6SS  of  internal  Cell-dlVlSlOn, 
yeast  "after  cultivation  on  a  piece  of  -1,1  ,  .,  ,  •,  ,,  -, 

carrot,  four  cells  forming  in  the  inte-  although    it    has    been    thought 

fiU&T^kVMR    to  be   of  greater  importance.! 
This  formation  of  new  cells  by 

internal  cell-division  appears  to  occur  only  when  the  supply 
of  nourishment  is  less  abundant,  as  when  the  yeast  is  grown 
on  cut  slices  of  potato  or  carrot. 


*  Made  as  follows  :  Potassium  phosphate,  20  parts  ;  calcium  phos- 
phate, 2  parts  ;  magnesium  sulphate,  2  parts  ;  ammonium  tartrate, 
100  parts  ;  cane  sugar,  1500  parts  ;  water,  8376  parts.  The  sugar  is 
to  be  omitted  in  some  cases. 

f  The  student  may  profitably  refer  to  Huxley  and  Martin's  "Ele- 
mentary Biology,"  Chap.  IV.,  for  directions  in  making  his  observations. 

$  Reess,  in  his  "  Botanische  Untersuchungen  iiber  die  Alcoholgilh- 
rungspilze,"  1870,  calls  this  process  the  formation  of  ascospores,  the 
mother-cell  he  calls  an  ascus,  and  the  daughter-cells  true  ascospores. 
Accordingly  he  considers  these  plants  to  be  very  simple  Ascoinycetes  ! 


CYANOPHYCE^;.  215 

280.— It  was  formerly  held  that  the  yeast  plant  was  only 
the  immature  condition  of  a  mould  ;*  but  Brefeld's  re- 
searches, f  which  were  undertaken  to  determine  whether 
true  yeast  ever  develops  into  a  filamentous  form,  appear  to  be 
decisive  against  that  view.  He  found  that  under  different 
conditions,  as  with  free  access  of  air,  or  growth  in  a  thin 
stratum  of  a  neutral  solution,  the  results  were  always  nega- 
tive, and  no  filamentous  forms  appeared. 

(a)  Examinations  of  the  yeast  plant  are  easily  made  by  placing  a 
very  small  drop  of  active  yeast  upon  a  glass  slide,  and,  after  covering 
it  in  the  usual  way,  keeping  it  in  a  warm  and  moist  chamber  for  some 
hours,  at  the  end  of  which  time  the  "budding"  will  have  become 
quite  well  marked.  A  slide  so  prepared  may  be  examined  immedi- 
ately, but  with  less  satisfactory  results. 

(6)  Yeast  may  be  grown  in  abundance  by  placing  a  few  drops  in  a 
quantity  of  Pasteur's  solution,  in  which  it  grows  with  great  rapidity 
in  a  temperature  of  30°  to  35°  C.  (about  90°  Fahr.). 

(c)  The  state  in  which  daughter-cells  are  formed  may  be  developed 
by  growing  the  yeast-cells  (those  called  bottom  yeast  are  the  most  sat- 
isfactory) upon  fresh-cut  slices  of  potato,  kohl-rabi,  carrot,  or,  better 
still,  upon  small  slabs  of  plaster  of  Paris.     Tlie  preparations  must  be 
kept  moist  by  covering  with  a  bell-jar  ;  with  proper  care  the  formation 
of  daughter-cells  will  be  seen  in  a  week  or  ten  days  from  the  begin- 
ning of  the  experiment. 

(d)  In  order  that  the  study  of  these  organisms  may  be  at  all  satisfac- 
tory the  student  should  be  provided  with  high  powers  of  the  micro 
scope,  say  from  600  to  800  diameters.:}: 

§  III.   CLASS  CYAN-OPHYCE.E. 

281. — These  are  blue-green,  verdigris-green,  brownish 
green,  or  rarely  purple  or  red  Protophytes,  which,  in  addi- 
tion to  chlorophyll,  contain  a  soluble  coloring-matter — 


*  "Yeast  is,  in  fact,  nothing  more  than  a  peculiar  condition  of  a 
species  of  Penicillium,  which  is  capable  of  almost  endless  propagation 
without  ever  bearing  perfect  fruit."  Berkeley's  "  Introduction  to  Cryp- 
togamic  Botany,"  1857,  p.  299. 

f  In  Flora,  1873. 

|  The  student  is  again  referred  to  Huxley  and  Martin's  "  Elemen- 
tary Biology;"  in  Chap.  I.  will  be  found  a  valuable  account  of  the 
yeast  plant,  with  directions  for  making  examinations. 


216  BOTANY. 

pliycocyanine — and  a  less  soluble  one — phycoxanlliine.* 
Structurally  the  members  of  this  class  differ  but  little  from 
the  Schizomycetes,  although  they  are  of  a  much  larger  size. 
The  cells  generally  show  a  little  more  coherence  than  in  the 
last  class. 

They  live  in  fresh  or  stagnant  water,  or  upon  damp 
ground,  rocks,  or  decaying  wood.  Unlike  the  Schizomycetes, 
they  do  not  normally  inhabit  putrid  solutions. 

282.— Order  Chroococcacese.  This  is  made  up  of  uni- 
cellular plants.  The  cells,  which  are  spherical,  oblong,  cylin- 
drical, or  angular,  are  either  single,  or  more  commonly  united 
by  a  common  jelly  into  families.  Cell-division  (in  reality 
internal  cell-division)  takes  place  in 
either  one,  two,  or  three  planes  (Fig. 
147). 

Four  genera  are  known   in  the  United 
States,  viz.,  (1)   Chroococcus,  with  globose, 
oval,  or  angular  (from  pressure)  cells,  which 
are  solitary  or  in   free  families ;  our  three 
species  grow  on  wet  rocks  or  in  springs;  (2) 
Glceocapsa  (Fig.  147),  with  spherical  cells, 
which  are  solitary  or  in  enclosed  families  ; 
Fte7l47.- Glceocapsa  in  dif-    °«r  8'nRle  species  forms  a  firm  grumous  or 
ferent  stages  of  growth,  show-    gelatinous    coating   of  a  light  brown  color 
tion.mThc  daughter cel'ls  'are    on  wet  rocks  ;  (3)  Ckeosphcerium,  with  very 
™ari™UoM!hei£ot^  small  cells, forming  a  thallus-like  mass;  we 

youngest ;  E,  oldest  stage!  have  one  species,  forming  a  light-colored 
X  300.— After  Sachs.  gcum  on  8tagnant  water  ;  (4)  Jferismopedia, 

with  globose,  oval,  or  oblong  cells,  which  occur  in  tabular  families  of 
four,  eight,  sixteen,  etc. ;  our  two  species  inhabit  streams  and  fresh 
ponds. 

283.— Order  Nostocacese.     The  plants  of  this  order  are 

*  Pliycocyanine,  the  blue  coloring-matter,  is  extracted  from  the 
crushed  plants  by  cold  water  ;  the  solution  is  blue  by  transmitted  and 
blood-red  by  reflected  light.  After  the  extraction  of  pliycocyanine, 
treatment  of  the  crushed  plants  with  strong  alcohol  produces  a  green 
solution  which  contains  chlorophyll,  and  a  yellow  coloring-matter, 
phycoxanthine ;  the  latter  may  be  separated  by  shaking  up  with  the 
<!reen  solution  a  large  quantity  of  benzine,  which  takes  up  the  chloro- 
phvll,  and  when  at  rest  rises  and  forms  a  green  upper  layer  containing 
chlorophyll,  below  which  is  the  yellow  alcoholic  solution  of  phycoxun- 
thintj. 


CYANOPHYCEJE.  217 

composed  of  rounded  cells  loosely  united  into  a  filament  and 
generally  imbedded  in  jelly  (Fig.  148,  A)  ;  they  frequently 
form  large  masses,  united  by  the  glutinous  jelly.  At  inter- 
vals in  the  filaments  there  are  larger  clear  cells — the  hetero- 
cysts — which  appear  from  analogy  to  be  reproductive  bodies, 
although  nothing  is  positively  known  as  to  their  function. 
The  usual  mode  of  reproduction  is  by  the  simple  fission  of 
the  cells.  New  masses  or  colonies  are  formed  by  the  break- 
ing up  of  the  old  filaments  into  pieces  composed  of  a  few 
cells,  which  then  become  endowed  with  a  power  of  motion 
which  consists  of  a  slow  bending  from  side  to  side  with  a 
forward  movement  at  the  same  time.  Each  moving  fila- 
ment, when  it  comes  to  rest,  may  become  the  centre  of  a 
new  colony,  which  arises  from  it  by  fission. 

Four  genera  and  twenty  or  more  species  are  known  in  the  United 
States.     The   principal  genus 
is    Nostoe  (Fig.  148,    A) ;    its 
species  form  jelly-like  masses 
from  the  size  of  a  pin-head  to 
several  inches  in  diameter  in 
ponds  and   streams,  adhering 
to  sticks  and  twigs,  and  on  wet       Fig.  148.— ,1,  a  filament  of  a  Xostoc,  with  a 
rocks   or    wet    ground;    they   *ffi£*^J^^ 
even    grow    inside    of    other 

plants — e.g.,  Anthoceros  Icevis — and,  according  to  the  present  view,  con- 
stitute the  so-called  gonidia  of  certain  lichens. 

284.— Order  Oscillatoriacese.  The  filaments  in  this  or- 
der are  composed  of  more  closely  cohering  cells  than  in  the 
previous  one ;  the  cells  unite  by  broad  surfaces  to  form  a 
rigid,  cylindrical,  straight  or  slightly  curved  filament  (Fig. 
148,  B).  They  form  dark-green,  loose,  or  felted  masses  in 
water  or  on  wet  earth,  and  are  remarkable  for  the  peculiar 
oscillating  movements  of  their  filaments.  No  other  method 
of  reproduction  than  by  fission  is  known. 

The  principal  genus  is  Oacillatoria,  of  which  we  have  at  least  half 
a  dozen  species. 

285.— Order  Rivulariaceae.  The  filaments  in  this  order 
present  a  greater  differentiation  than  in  any  of  the  preced- 
ing ;  they  are  usually  arranged  in  a  radiating  manner,  and 
imbedded  in  a  common  jelly,  so  as  to  form  small  rounded 


218  BOTANY. 

masses.  Each  filament  has  a  basal  cell  (which  is  spherical 
and  thick  walled),  and  sometimes  interstitial  ones ;  the  prin- 
cipal cells  of  the  filaments  are  usually  cylindrical  and  often 
much  elongated  ;  at  the  outer  end  they  become  attenuated 
into  long  slender  hyaline  hairs.  Special  reproductive  bod- 
ies, called  resting  spores,  are  formed  before  the  close  of  the 
growing  season  ;  these  appear  just  above  the  basal  cells,  one 
on  each  filament,  and  are  much  larger  and  thicker  walled 
than  the  remaining  cells.  Upon  the  death  of  the  mass  of 
filaments  the  resting  spores  remain,  and  from  these  upon  the 
advent  of  favorable  conditions  new  filaments  are  developed. 

Seven  genera  are  known  in  the  United  States,  the  principal  ones 
being  Rivularia,  Zonotrichia,  and  Mastigonema ;  their  species  are 
found  in  water  or  wet  places  everywhere  ;  they  also  constitute  the 
so-called  gonidia  of  lichens. 

286.— Order  Scytonemacese.  In  this  order  the  differen- 
tiation becomes  so  great  that  the  filaments  may  be  said  to 
attain  a  distinct  individuality  ;  they  branch  here  and  there, 
and  are  furnished  with  thick- walled  heterocysts,  which  are 
basal  or  interstitial.  In  this  order  there  is  also  a  well-de- 
veloped sheath  surrounding  each  filament,  which  may  be 
compared  with  the  poorly  defined  one  of  the  preceding 
orders.  The  filaments  form  little  masses  or  mats,  growing 
in  the  water  or  on  wet  ground,  or  even  on  the  moist  bark  of 
trees. 

We  have  tliree  genera,  the  principal  one  of  which  is  Scytonema, 
wliich  contains  eleven  species.  Some  of  these  are  the  "gonidia"  of 
lichens. 

287. — Closely  related  to  the  foregoing  orders,  but  not 
falling  within  the  class  Cyanophyceae,  is  the  doubtful  order 
Palmellacece.  The  cells  are  single  or  in  colonies,  and  im- 
bedded in  a  gelatinous  matter,  much  as  in  the  Chroococcaceae  ; 
but  the  cells  are  destitute  of  phycocyanine  or  phycoxanthine, 
containing  only  chlorophyll.  This,  however,  is  hardly  a 
sufficient  character  for  separating  them.  It  is,  moreover, 
not  certainly  known  whether  the  forms  included  in  this 
order  are  autonomous  species  ;  it  seems  probable  that  at 
least  a  portion  of  them  are  only  early  stages  of  other  plants. 


CYANOPHYCE^E. 


219 


288. — The  genera  Protococcus,  C'hlorococcum,  and  one  or 
two  others,  are  probably  to  be  placed  nc  ar  the  Palmellaceae, 
although  their  autonomy  is  doubtful  also.  They  are  all 
unicellular  in  the  strictest  sense  of  the  term,  and  reproduce 
mainly  by  fission.  In  their  resting  stage  they  are  spheroidal ; 
in  their  motile  stage  they  are  provided  with  two  cilia.  The 
latter  form  is  said  to  arise  from  the  former  by  internal  cell- 
division,  which  results  in  the  production  of  "gonidia"of 
two  sizes,  the  larger  being  termed  macrogonidia,  and  the 
smaller  microgonidia. 

These  organisms  are  common  in  shallow  pools,  in  the  gut- 
ters of  roofs,  and  on  the  wet  earth. 

(a)  On  account  of  their  ready  perishability,  Protophytes  are  scarcely 
found  in  a  fossil  state.  Sckiinper  records  a  species  of  Nostoc  from  the 
Tertiary. 

(6)  The  relationship  of  the  classes  of  the  Protophytes  may  be  indi- 
cated by  the  following  diagram  : 


ARRANGEMENT  OF  THE  CLASSES  OF  PROTOPHYTA. 

Cyanophycese. 


Myxomycetes. 


Schizomycetes. 


CHAPTER   XV. 

ZYGOSPORE^E. 

280. — This  is  an  assemblage  of  quite  simple  plants,  none 
of  its  members  attaining  any  great  degree  of  complexity. 
For  the  most  part  the  plant-body  consists  of  an  elongated 
filament  composed  of  united  cells ;  sometimes,  however, 
they  form  surfaces,  and  in  other  cases  the  plants  are  unicell- 
ular, or  aggregated  into  communities.  In  these  plants  we 
find  the  first  examples  of  undoubted  sexuality,  and  through- 
out the  group,  the  organs  and  methods  of  fertilization  are 
nearly  enough  uniform  to  enable  us  to  use  them  as  distin- 
guishing characters.  The  sexual  organs  all  have  this  in  com- 
mon, that  between  the  male  and  the  female  there  is  no  ap- 
preciable difference  as  to  form,  size  (with  a  few  exceptions), 
color,  origin,  etc.  In  the  sexual  processes,  likewise,  there  is 
this  in  common,  that  the  result  of  the  union  of  the  two 
sexual  cells  is  the  production  of  a  new  cell,  the  zyyoxporc, 
possessing  very  different  characteristics  from  either.  While 
the  sexual  cells  have  only  ordinary  walls,  or  none  at  all,  tho 
zygospores  are  covered  with  thick,  firm  walls. 

290. — The  zygospore  is  frequently  called  the  "  resting 
spore,"  because  under  certain  circumstances  it  remains  quies- 
cent, while  retaining  its  vitality,  often  for  long  periods  of 
time.  Thus  at  the  close  of  the  growing  season,  as  upon 
the  advent  of  the  summer  drought,  or  of  winter,  the  zygo- 
spores fall  to  the  bottom  of  the  pools  (in  the  aquatic  forms), 
and  in  the  dried  or  frozen  mud  remain  uninjured  until  the 
return  of  favorable  conditions,  when  they  germinate  and  give 
rise  to  a  new  generation  of  plants. 

291. — Nearly  all  the  plants  of  this  group  contain  chloro- 
phyll, only  one  order  being  destitute  of  it.  The  green  forms 
are  all  aquatic,  and  inhabit  either  fresh  or  salt  water.  They 


ZOOSPORES.  221 

include  the  greater  part  of  the  green  algae  of  our  ponds 
and  streams.  Those  which  have  no  chlorophyll  are  sapro- 
phytes, and  live  upon  dead  organic  matter.  They  are  doubt- 
less to  be  regarded  as  modified  forms  of  some  of  the  types 
of  the  chlorophyll-bearing  portion  of  the  group. 

§  I.    CLASS  ZOOSPOREJS. 

202. — This  class  is  a  somewhat  doubtful  one  ;  it  is  com- 
posed of  plants  which,  while  differing  in  many  other  re- 
spects, agree  in  having  locomotive  sexual  cells  (zoospores). 
In  this  they  agree,  however,  with  the  Volvocinece,  and  bear 
a  close  resemblance  to  Protococcus  and  its  allies.  It  is  prob- 
able that  a  fuller  knowledge  of  some  of  the  plants  of  this 
class  will  result  in  their  being  distributed  elsewhere. 

The  general  structure  of  the  plants  referred  to  this  class 
may  be  understood  from  the  examples  which  follow.  No  at- 
tempt will  be  made  here  to  indicate  the  orders  to  which 
they  belong. 

293. — Pandorina  is  a  unicellular  alga,  which  is  united  into 
colonies  (called  cwnobia),  which  swim  about  freely  in  the 
water  (A,  Fig.  149).  Each  colony  consists  of  sixteen  rounded 
or  pointed  cells,  each  provided  with  two  cilia  (called  zoogo- 
nidia), and  united  into  a  spherical  mass  by  a  gelatinous  enve- 
lope, through  which  the  cilia  project.  Each  zoogonidium 
breaks  itself  up  into  sixteen  new  zoogonidia,  forming  sixteen 
small  and  new  colonies  (B,  Fig.  149),  which  are  soon  set  free 
by  the  absorption  of  the  common  envelope  of  the  colonies. 
The  process  of  colony-formation  just  described  is  repeated 
again  and  again,  thus  giving  rise,  asexually,  to  a  large  num- 
ber of  colonies. 

294. — The  sexual  process  begins  in  the  same  way  ;  but  the 
zoogonidia  of  the  new  colony  separate  by  the  softening  of 
the  colony-envelope  (  0  and  D,  Fig.  149),  becoming  zoospores, 
which  are  naked  protoplasm-masses,  which  swim  about  by 
means  of  their  cilia.  After  a  time  two  zoospores  meet,  their 
points  coming  in  contact,  and  their  bodies  soon  fusing  into 
one  common  body  (E,  F,  G,  Fig.  149).  The  result  of  this 
union,  which  is  regarded  as  a  very  simple  kind  of  sexual 


i>22 


BOTANY. 


act,  is  that  within  a  short  time  a  thick  coat  of  cellulose  is 
formed  over  the  new  cell,  thus  producing  a  zygospore  (H, 
Fig.  149).  After  a  long  period  of  rest,  these  zygospores 


Fig.  149. — Pnndorina  Morum.  A,  non-sexual  colony  (or  ccEnobium)  of  16  zoogoni- 
dia ;  a,  red  spot;  b,  transparent  anterior  end  of  zoogonidium,  to  which  the  two 
cilia  are  attached. 

B,  sixteen  young  sexual  colonies  about  to  leave  the  gelatinous  wail. 

f^and  f),  colonies  of  sexual  zoospores  escaping. 

E,  F,  G,  conjugating  zoospores 

//,  zygospore  in  test  ins  stage  (red). 

J,  K,  germinating  zygospore,  the  contents  escaping  as  a  large  red  ciliated  swarm- 
epore. 

L,  new  colony  formed  by  the  division  of  K,  very  young  stage. 

Af,  the  same  colony  as  L,  in  a  further  stage  of  development. — After  CErsted. 

germinate  by  the  bursting  of  the  coat  (exospore),  when  the 
protoplasmic  contents  escape  as  a  ciliated  swarm-spore  (K, 
Fig.  149).  After  swimming  about  for  some  time,  the  swarm- 


ZOOSPORE^E.  223 

spores  absorb  their  cilia,  and  surround  themselves  with  a 
gelatinous  envelope,  when  each  breaks  up  into  sixteen  cells 
(zoogonidia)  and  gives  rise  to  a  new  colony  (L  and  M,  Fig. 
149). 

Pandorina  is  nearly  related  to  Volvox  (see  p.  243),  from 
which  it  seems  a  violence  to  separate  it.  It  occurs  in  pools 
of  fresh  water  (in  Europe)  as  minute  green  spherical  ccenobia, 
3  mm.  (.012  inch)  in  diameter. 

295. — Hydrodictyon,  the  Water  Net,  is  a  common  plant 
in  ponds  and  sluggish  streams.  It  is,  when  full  grown,  a 
tubular  net,  composed  of  a  multitude  of  elongated  cells, 
which  are  attached  only  at  their  ends  ;  the  net  sometimes 
attains  a  length  of  25  to  30  centimetres  (10  to  12  inches), 
and  the  cells  Avhich  compose  the  meshes  are  in  such  speci- 
mens 7  to  8  mm.  (£  inch)  long.  The 
reproduction  is  as  follows  :  The  pro- 
toplasmic contents  of  certain  cells 
break  up  into  a  large  number  of 
daughter  -  cells  (macrozoogonidia), 
there  being  often  as  many  as  7000  to 
20,000;  these  soon  arrange  them- 

Selves    within    the    mother-Cell    SO    as  are  beginning  to  arrange  them- 

.     .  .  „    .  welves  so  as  to  form  a  minia- 

to   form   a  miniature    net    (rig.    loO),  ture  net  within   tue  mother- 

,  .   ,      .       .        ,    ,       ,,          ,  ,.  *  cell.— After  (Ersted. 

which  is  freed  by  the  absorption  of 

the  walls  of  the  mother-cell.  Under  favorable  conditions 
the  young  net  attains  full  size  within  a  month.  A  second 
mode  of  reproduction  is  known,  or  partly  known.  In  cer- 
tain cells,  in  the  division  of  their  protoplasmic  contents,  in- 
stead of  giving  rise  to  the  comparatively  large  macrozoogo- 
nidia, they  produce  an  extremely  large  number  (30,000  to 
100,000)  of  very  small  ciliated  swarm-spores  (zoospores,  or 
the  clironizoospores  of  Pringsheim),  which,  after  swimming 
about  for  a  time,  acquire  thick  walls,  and  fall  to  the  bottom 
of  the  water,  where  they  remain  in  a  resting  state.  Upon 
their  germination  they  pass  through  a  number  of  curious 
stages,  and  finally  give  rise  to  small  nets.  Suppanetz  is  said 
to  have  witnessed  the  conjugation  of  the  swarm-spores  within 
the  mother-cell,  or  immediately  after  their  emission.* 

*  Qr.  Jour.  M.c.  Science,  1875,  p.  399. 


224 


BOTANY. 


296.— Closely  related  to  Hydrodictyon  is  Pediastrum  (Fig. 
151), which  consists  of  a  number  of  cells  arranged  into  a 
flat,  thallus-like  mass.  The  cells  at  a  certain  stage  produce,  by 


Fig.  151.—  A,  a  colony  of  cells  constituting  a  so-called  individual  of  Pediastrum 
graiiulatum  ;  t,  cells  with  their  contents  remaining  ;  the  white  cells  are  empty,  their 
contents  having  escaped  by  the  slits  sp  :  a.  contents  of  a  cell  (mnci  ozoogronidia) 
escaping.  B,  macrozoogonidia  g,  in  the  motile  state,  enclosed  in  the  membrane  b.  C, 
the  macrozoogonidia  arranging  themselves  in  a  colony,  still  unclosed  by  the  mem- 
brane b.  X  400.—  After  Braun. 

internal  cell-division,  a  large  number  of  daughter-  cells,  which 
are  of  two  sizes.     The  function  of  the  smaller  ones  is  un- 
0  known  ;    the   larger   ones 

(macrozoogonidia)  escape 
by  a  slit  in  the  wall  of  the 
mother-cell,  surrounded  by 
a  thin  membrane,  in  which 
they  swim  freely  for  a  time 
(Fig.  151  B).  After  a 
while  they  lose  their  pow- 
er of  motion  and  arrange 
themselves  symmetrically, 
as  in  C,  Fig.  151.  They 
soon  grow  together,  and 

n  V.  ««!,«.«    Kl™ 

tllUS    form    a    COlOll)     like 

.]  „  n.ironj-  OT1P 
u  >lle' 

297.  —  111      ClofophWA 

(one  of  the  common  Confervaceae)  the  cells  of  the  branching 
filaments  break   up  into  ciliated    /.oospoivs    which    directly 


Fig.  152.—  Portion  of  the  thailus  of  Viva,  a, 
cells  filled  with  /oospores  (zoognnidia)  ;  b, 
opening  in  cell-wall  by  which  the  zoospores 
escape  from  the  cells;  c,  zoospores  (zoogo- 
nidia).-After  O3r*ted. 


DESMIDIACE^E.  225 

reproduce  new  filaments.     Smaller  bodies — swarm-spores — 
are  also  produced,  and  these  are  said  to  conjugate.* 

298. — In  Ulva  the  plant-body  is  flat,  and  composed  of  a 
single  layer  of  polyhedral  cells,  in  which  are  found  zoospores, 
which  are  asexual  (Fig.  152,  c),  and  smaller  swarm-spores, 
which  are  said  to  conjugate.! 


§  II.    CLASS  CONJUGATE. 

299. — In  this  class  the  sexual  process  is  a  distinct  conju- 
gation, and  it  always  takes  place  in  the  mature  plant. 
Swarm-spores  are  wanting.  The  orders  of  this  class  are  well 
marked. 

300.— Order  Desmidiacese.  The  Desmids  are  minute  uni- 
cellular algae  ;  the  cells  are  of  very  various  forms,  mostly 
more  or  less  constricted  in  the  middle,  and  divided  into  two 
symmetrical  half-cells ;  they  are  free,  or  united  into  loose 
families,  sometimes  involved  in  a  jelly.  The  cell-wall  is 
more  or  less  firm,  but  not  silicious. 

3O1. — The  reproduction  of  Desmids  takes  place  asexually 
and  sexually.  In  the  first  the  neck  uniting  the  two  halves 
of  the  cell  elongates  and  becomes  divided  by  a  transverse 
partition,  so  that  instead  of  the  original  symmetrical  cell 
there  are  now  two  exceedingly  unsymmetrical  ones ;  these 
grow  by  the  rapid  enlargement  of  the  new  and  small  halves  ; 
eventually  the  two  cells  become  symmetrical,  by  which  time 
they  have  separated.  This  process,  Avhich  is  essentially  fis- 
sion, may  be  repeated  again  and  again. 

The  sexual  process  takes  place  in  this  way  :  each  of 
two  cells  which  are  near  one  another  sends  out  from  its 
centre  a  conjugating  tube,  which  meets  the  corresponding 
one  from  the  other  (d,  Fig.  153).  At  the  point  of  meeting 
the  two  tubes  swell  up  hemispherically,  and  finally,  by  the 
disappearance  of  the  separating  wall,  the  contents  unite  and 
form  a  rounded  zygospore  (e,  Fig.  153),  which  soon  becomes 


*  and  f.    Areschoug,  in  "  Observationes  Phycologica?,"  1874,  records 
having  seen  the  conjugation  in  Cladophom  and  Ulva,. 


226 


BOTANY. 


coated  with  a  thick  wall  (/,  Fig.  153).  This  zygospore  is  a 
resting  spore,  and  may  retain  its  vitality  for  an  indefinite 
period. 

302. — In  the  germination  of  the  zygospore  the  first  notice- 
al)k'  change  is  the  partial  separation  of  the  contents  into  two 
portions,  and  the  escape  of  the  whole,  surrounded  by  a  deli- 
cate wall,  through  a  rent  in  the  exospore  (y,  h,  Fig.  153) ; 
the  separation  of  the  protoplasm  now  becomes  complete 
(/',  Fig.  153),  and  each  portion  becomes  again  partly  divided 
by  lateral  constrictions,  which,  however,  do  not  quite  reach 
the  centre  ;  in  this  way,  within  the  mass  which  escaped  from 
the  zygospore  there  are  formed  two  constricted  cells,  which 


Fig.  153.— Conjugation  of  Costnarium  Mtnenghinti.  a,  front ;  b,  end  ;  c,  side 
view  of  the  adult  plnnts ;  4,  two  cells  conjugating:  c,  young  /.ygospore  formed;  f, 
ripe  zygospore,  with  spiny  wall— the  four  halves  of  the  p  u-eiu  cells  are  empty  ;  q. 
the  zygospore  germinating  after  a  period  of  rest ;  A,  the  young  cell  escaped  froin 
zygospore  ;  i,  young  cell  dividing,  showing  two  new  plants  similar  to  a,  placed 
crosswise  in  the  interior  of  the  cell.  X  475. — After  (Ersted. 

are,  in  fact,  new  individuals  resembling  the  original  ones 
which  conjugated  (a,  i,  c,  Fig.  153). 

The  descriptions  above  given  are  of  the  processes  as  they 
take  place  in  the  bilobed  Desmids  ;  in  those  which  are  not 
lobed  it  takes  place  in  essentially  the  same  way,  with  differ- 
ences only  in  the  minor  details. 

303. — Desmids  have  the  power  of  slow  locomotion,  and 
they  may  often  be  seen  moving  across  the  field  of  the  micro- 
scope, or  in  a  jar  or  bottle  they  may  frequently  be  seen  to 
congregate  in  particular  places.  The  mechanism  of  the 
movement  is  unknown,  but  it  appears  to  be  certain  that  it  is 
not  ciliary. 

Desmids  are  exclusively  inhabitants  of  fresh  water  (not 
salt),  and  in  almost  all  cases  they  appear  to  prefer  pure  and 


DZATQXAQR&. 

clear  water  to  that  which  is  stagnant,  although  they  are  to  be 
found  in  the  latter  also. 

The  principal  genera  are  Cosmanum  (Fig.  153),  Eaaxtrum  and 
Micrasterias,  which  are  constricted  in  the  middle  ;  and  Closterium,  in 
which  the  individuals  are  cylindrical  or  fusiform.* 

304.— Order  Diatomacese.t  The  Diatoms  are  micro- 
scopic unicellular  algne,  resembling  in  man)  particulars  the 
Desmids,  but  differing  from  them  in  having  walls  which  are 
silicified,  and  in  the  chlorophyll  being  hidden  by  the  pres- 
ence of  phycoxanthine.  The  endochrome,  as  the  colored 
contents  are  called,  is  always  symmetrically  arranged.  Each 
cell  (technically  called  a  frustule)  is  usually  composed  of  two 
similar  and  approximately  parallel  portions,  called  the  valves. 
Each  valve  may  be  described  as  a  disc  whose  edge  is  turned 
down  all  around,  so  as  to  stand  at  right  angles  to  the  remainder 
of  the  surface,  making  the  valve  have  the  general  plan  of  a  pill- 
box cover.  The  two  valves  are  generally  slightly  different 
in  size,  so  that  one  slips  within  the  other  (A,  Fig.  154),  thus 
forming  a  box  with  double  sides.  In  other  cases — as,  for  ex- 
ample, in  Diatoma  and  Fragilaria — the  valves  are  simply 
opposed,  and  do  not  overlap.  In  figures  and  descriptions  of 
Diatoms,  the  parts  corresponding  to  the  top  and  bottom  of  a 
box  are  referred  to  as  the  valve?,  or  as  the  side  view  (C,  Fig. 
154),  and  that  which  in  the  box  would  be  called  the  side,  is 
in  the  Diatom  called  the  front. 

305. — The  individuals  may  exist  singly,  or  in  loose  fami- 
lies ;  they  are  free,  or  attached  to  other  objects  by  little 
stipes,  and  they  are  frequently  imbedded  in  a  mucous  secre- 
tion. The  free  forms  are  locomotive,  and  may  be  seen  in 
constant  motion  under  the  microscope.  As  in  the  Desmids, 
the  mechanism  of  this  movement  is  not  certainly  known  ; 


*  The  student  is  referred  to  Dr.  H.  C.  Wood's  "  Contribution  to  the 
History  of  the  Fresh-water  Algae  of  North  America,"  1872,  for  an  ac- 
count of  our  species. 

f  Pfitzer  and  others  maintain  that  the  name  Bacittariicece  should  be 
applied  to  this  order. 


228 


BOTANY. 


the  most  probable  explanation  is  that  it  is  due  to  protrusions 
of  the  protoplasm  through  orifices  in  the  rigid  wall. 

306. — Diatoms  bear  a  close  resemblance  to  the  Desmids 
in  their  modes  of  reproduction  ;  the  differences  that  exist 
are  easily  referable  to  the  differences  in  the  wall.  The 
asexual  reproduction  is  a  true  fission,  although  at  first  sight 
it  might  not  be  recognized  as  such.  The  protoplasmic  con- 
tents of  the  cells  divide  in  a  plane  parallel  to  the  valves ; 
each  portion  then  forms  a 
new  valve  in  the  plane  of  the 
division.  As  during  this  pro- 
cess the  two  original  valves  are 
pushed  apart,  the  new  valves 
are  fitted,  the  one  into  the 
larger  and  the  other  into  the 
smaller  one  (B,  Fig.  154).  By 
a  slight  subsequent  increase 
of  their  contents,  the  two 
daughter-cells  are  pushed  out 
so  as  to  be  free  from  each 
other  ;  in  many  cases  they  sep- 
arate, while  in  others  they  re- 
main in  contact,  although 
really  free.  This  process  re- 

A,  front    nll;,,oa  fvnm  +lirno   fr»   -frmv  rlo^o 
view  of  a  frustule  :  B.  front  view  of  a    <JU1I8B  II  Olll  tlirCC   tO   IOU1  days 

for    its  completion.      It    will 
S;  readily  be  **?  that  the  con- 
—After  (Ereted.  tmued  formation  of  individu- 

als in  this  way  must  result,  in  all  species  whose  valves  are  of 
a  slightly  unequal  size,  in  producing  smaller  and  smaller 
cells.  This  reduction  of  size  does  not,  however,  take  place 
in  those  species  whose  valves  are  simply  opposed,  as  in  Dia- 
toma.  The  reduction  of  size  is  corrected  by  the  formation 
of  what  are  termed  Auxospores  ;  *  these  are  large  individu- 
als, which  form  either  by  an  asexual  or  a  sexual  process. 
The  asexual  formation  of  auxospores  takes  place  by  the 


*  From  the  Greek  aiifdvu,  to  increase. 


DJATOMACE.fi. 


229 


protoplasm  of  one  of  the  small  Diatoms  leaving  its  silicious 
shell  (the  latter  falling  apart),  and  then  increasing  by  growth 
until  it  reaches  the  normal  size,  when  it  forms  a  new  coat 
about  itself.  This  is  not  unlike  what  has  been  called  the 
Rejuvenescence  of  the  cell.  (See  p.  42.) 

3O7. — The  second  mode  of  the  formation  of  auxospores  is 
a  sexual  one,  and  is,  in  fact,  the  sexual  mode  of  reproduc- 
tion above  referred  to.*  Two  individuals  come  near  each 
other  ;  their  valves  separate,  and  the  two  protoplasm-masses 
unite  with  each  other  into  one  mass,  or  in  many  cases  two 
masses  (A,  Fig.  155).  These  new  masses  develop  directly 
into  auxospores,  the  whole  process 
requiring  from  ten  to  fourteen 
days  (B,  Fig.  155). 

308. — Diatoms  are  exceedingly 
abundant ;  they  occur  in  both 
salt  and  fresh  water,  usually 
forming  a  yellowish  layer  at  the 
bottom  of  the  water,  or  they  are 
attached  to  the  submerged  parts  of 
other  plants,  and  to  sticks,  stones, 
and  other  objects  ;  they  have  been 
dredged  from  the  ocean  at  great 
depths,  and  appear  to  exist  there 
in  enormous  quantities.  They  are  ehowing™coiyugat 

,        .  ,  J  tion  of  anxospore.    ^,      nu«'a- 

also  found  among  mosses  and  other  tion  of  two  fmsmies ;  £,  two  aux- 
plants  on  moist  ground;  great  ST^i  "pSem  frSSSie^-lfter' 
numbers  occur  as  fossils,  forming  CErsted- 
in  many  instances  vast  beds  composed  of  their  empty 
frustules.  The  varied  and  frequently  very  beautiful  mark- 
ings of  their  valves  have  long  made  Diatoms  objects  of 
much  interest  to  the  microscopist.  The  great  regularity 
and  the  extreme  fineness  of  the  lines  and  points  upon  some, 
have  caused  them  to  be  used  as  microscopic  tests.  The 


saasonica, 
nd  forma- 


*  This  process  takes  place  at  certain  seasons  of  the  year  for  each 
species  ;  according  to  Professor  H.  L.  Smith,  in  Gomphonenui  olivaceum 
it  occurs  in  February  and  March 


230  BOTANY. 

fineness  of  some  of  these  markings  is  astonishing,  as  will 
be  seen  from  the  following  list : 

*Pleurotdgma  Balticum 0006  mm.  (.000026  inch). 

Pleurodyma  angultitum 0005    "      (.000019    " 

Navlcula  rhomboids 0004    "      (.000015    " 

AmpMpleura pellucida 0002    "      (.000008    " 

(a)  The  classification  of  Diatoms  is  as  yet  largely  artificial.  That 
proposed  by  Professor  H.  L.  Smith  f  is  one  of  the  most  satisfactory  ;  it 
is  based  upon  the  structure  of  the  frustule.  He  divides  the  order  into 
three  tribes,  each  containing  several  families,  as  follows  : 

TKIBE  I.   RAPHIDIE.E. 

Frustules  mostly  bacillar  (i.e.,  longer  than  broad) ;  always  with  a  dis- 
tinct raphe  or  median  line  on  one  or  both  valves,  and  with  central  and 
terminal  nodules  ;  without  teeth,  spines,  awns,  or  processes. 

Family  1.  Cymbelleee.  Haphe  mostly  curved  ;  valves  alike,  more 
or  less  arcuate,  cymbiform  (i.e.,  lunate). 

Illustrative  genera,  Amphora,  CymbeUa. 

Family  2.  Naviculeee.  Valves  symmetrically  divided  by  tin; 
raphe  ;  frustules  not  cuneate  or  cymbiform. 

Navicula  (Figs.  154  and  155),  Stauroneis,  Pkurosigma,  Amphi- 
pleura. 

Family  3.  Gomphonemese.  Valves  cuneate  ;  central  nodule  un- 
equally distant  from  the  ends. 

Gomphonema,  Rhoicosphenin . 

Family  4.  Achnantheae.  Frustules  genuflexed ;  nodule  or  attiu- 
ros  on  one  valve  ;  mostly  stipitate. 

Achnanthes,  AcJmanthidium. 

Family  5.  Cocconideee.  Frustules  (generally  parasitic)  with  valves 
unlike  ;  valves  broadly  oval. 

Goceoneis,  Anortheis. 

TRIBE  II.   PSEUDO-RAPE IDIE^;. 
Frustules  generally  bacillar  (i.e.,  longer  than  broad)  ;  valves  with- 

*  These  measurements  are  those  given  in  Carpenter's  work  on  "  The 
Microscope,"  fifth  edition,  p.  212.  Those  given  by  Professor  Morley,  in 
Am.  Naturalist,  1875,  p.  429,  are  a  trifle  less  in  each  case. 

f  "  Conspectus  of  the  Families  and  Genera  of  the  Diatomaceae,"  by 
H.  L.  Smith,  published  in  Th:  Lem,  1872-3,  and  republished  in  Le 
Micr  wope,  s i  construction,  etc.,  by  Henri  Van  Heurck,  1878. 

The  brief  sketch  of  this  system  of  classification  here  given  is  fur- 
nished by  Professor  Smith. 


DIATOMACEJE.  231 

out  a  true  raplie  ;  without  central  and  marginal  nodules  ;  without 
teeth,  processes,  or  spines. 

Family  6.  Fragilarieee.  Frustules  adherent,  forming  a  ribbon- 
like,  fan-like,  or  zigzag  filament,  or  attached  by  a  gelatinous  cushion 
or  stipe  ;  sometimes  arcuate  in  front,  or  side  view. 

Epithemia,  Eunolia,  Fragilaria,  Synedra,  Diatomi. 

Family  7.  Tabellariese.  Frustules  with  internal  plates,  or  imper- 
fect septa,  often  forming  a  filament. 

Climacosphenia,  Orammatophora,  Rhtibdonema,  Tabellaria,  Stria- 
teUa. 

Family  8.  Surirellese.  Frustules  alate,  or  carinate ;  frequently 
cuneate  in  front  view  and  side  view. 

Nilzxchia,  SurirMt,  Cymat  -pleura. 

TRIBE  III.   CRYPTO-RAPEIDIE/E. 

Frustules  cylindrical  or  angular  ;  frequently  with  processes,  spines, 
teeth,  or  awns  ;  and  often  coherent,  forming  a  filament. 

Family  9.  Chaetocereae.  Frustules  mostly  hyaline  and  armed 
with  bristles  or  awns,  and  generally  coherent. 

Rhizosolenia,  Chcetoceros. 

Family  10.  Melosirese.  Frustules  cylindrical,  adhering  and  form- 
ing a  stout  filament ;  valves  cylindrical,  sometimes  armed  with  spines. 

Melosira,  Stephanopyxi*. 

Family  11.  Biddulphieee.  Frustules  adherent,  forming  generally 
a  zigzag  filament,  attached  by  one  or  two  processes. 

Istkmin,  Terpsinoe,  Biddulp^ia,  Hemiaulus. 

Family  12.  Eupodisceaa.  Frustules  not  forming  a  filament ; 
valves  cylindrical,  with  ocelli  ;  often  with  radial  ribs  or  furrows. 

Aulucus,  Aulucodiscux,  Evpodi*cus. 

Family  13.  Heliopelfceae.  Valves  divided  into  compartments  al- 
ternately light  and  dark,  often  with  marginal  spines  or  teeth. 

Actinoptychui,  Heliopelt  i,  Halionyx. 

Family  14.  Asterolamprese.  Valves  circular  (rarely  angular)  and 
mostly  hyaline,  with  linear,  often  bifurcating,  rays. 

Actinodiacus,  Mattogonia,  Aslerolampra. 

Family  15.  Coscinodisceae.  Valves  circular,  generally  with  radi- 
ating cellules,  granules,  or  punctse  ;  sometimes  with  marginal  or  intra- 
marginal  spines  or  distinct  ribs  ;  without  distinct  processes. 

Cydottlla,  Actinocydu*,  Stephatiodissus,  Arachnoiducus,  Co&cino- 
discus. 

(b)  Diatoms  are  very  easily  obtained  for  study ;  it  is  only  necessary 
to  scrape  off  a  little  of  the  slippery  covering  of  submerged  stones  or 
sticks  to  procure  numerous  specimens.  They  may  be  obtained  also 
from  ordinary  drinking  water,  allowing  it  to  flow  from  a  hydrant 
through  a  filter  of  "  Canton  flannel "  for  an  hour  or  so.  Often  appar- 


232  BOTANY. 

ently  pure  water  placed  for  a  few  weeks  in  a  clean  bottle  and  exposed 
to  the  light  will  yield  an  abundant  crop,  generally  of  one  species. 

309.— Order  Zygnemacese.  The  plants  of  this  order  are 
elongated  unbranched  filaments,  composed  of  cylindrical 
cells  arranged  in  single  rows.  The  cells  are  all  alike,  and 
each  one  appears  to  be  independent,  or  nearly  so,  of  its  asso- 
ciates. The  filament  is  thus,  in  one  sense,  rather  a  com- 
posite body  than  an  individual.  Each  cell  has  usually  a 
centrally  placed  nucleus,  with  radiating  extensions  of  the 
protoplasm  passing  from  it  to  the  layer  lining  the  inner  sur- 
face of  the  wall.  The  chlorophyll  is  generally  arranged  in 
bands  or  plates,  but  under  certain  conditions  it  exists  in 
shapeless  masses. 

310. — The  vegetative  increase  of  the  number  of  cells  takes 
place  by  the  fission  of  the  previously  formed  cells.  The 
protoplasm  in  a  cell  divides,  and  a  plate  of  cellulose  forms  in 
the  plane  of  division.  This  is  repeated  again  and  again,  and 
by  it  the  filament  becomes  greatly  elongated.  It  is  interest- 
ing to  note  that  this  increase  of  cells,  which  here  constitutes 
the  growth  of  the  plant-body,  is  that  which  in  simpler  plants 
is  called  the  asexual  mode  of  reproduction.  In  the  plants 
under  consideration  there  is  barely  enough  coherence  of  the 
cells  to  enable  them  to  constitute  a  plant-body,  and  one  can 
readily  see  that  the  same  fission  of  the  cells  which  now  takes 
place,  and  which  here  increases  the  size  of  the  plant,  would, 
if  the  cells  cohered  less,  simply  increase  the  number  of  indi- 
viduals. 

As  might  be  expected,  the  filaments  occasionally  separate 
spontaneously  into  several  parts  of  a  considerable  length, 
and  the  parts  floating  away  give  rise  to  new  filaments.  The 
separation  takes  place  by  the  cells  first  rounding  off  slightly 
at  the  ends,  so  that  their  union  is  weakened  at  their  cor- 
ners ;  finally  only  the  centres  of  the  rounded  ends  are  left 
in  slight  contact,  which  soon  breaks. 

311. — The  sexual  reproduction  is  well  illustrated  in  Spi- 
rogyra,  one  of  the  principal  genera.  At  the  close  of  their 
growth  in  the  spring,  the  cells  push  out  little  processes  from 
their  sides,  which  extend  until  they  come  in  contact  wit!) 


ZYGNEMACE^E. 


233 


similar  processes  from  parallel  filaments  (a,  b,  Fig.  156). 
Upon  meeting,  the  ends  of  the  processes  flatten  upon  each 
other,  the  walls  fuse  together,  and  soon  afterward  become 
absorbed,  thus  making  a  channel  leading  from  one  cell 
to  the  other  (Fig.  157).  Through  this  channel  the  proto- 


Pio.  156. 

Fig  156.— Beginning  of  the  process  of  conjugation  m  Spirogyra  longata.  a, 
beginning  of  the  formation  of  lateral  tubes  ;  b,  c,  the  tubes  in  contact.  X  550. 
—After  Sachs. 

Fig.  157. — Conjugation  of  Spirogyra  longata.  A,  the  protoplasm  passing  from 
one  cell  to  the  other  at  a ;  b,  the  mass  of  protoplasm  formed  by  the  union  of  the 
protoplasmic  contents  of  the  two  cells. 

B,  two  young  xygospores  (c),  each  with  a  cell-wall.  They  contain  numerous  oil 
drops,  and  are  still  enclosed  by  the  walls  of  the  parent  cell,  x  550.— After  Sachs. 

plasm  of  one  cell  passes  into  the  other,  and  the  two  fuse  into 
one  mass,  which  becomes  rounded,  and  in  a  short  time  secretes 
a  wall  of  cellulose  around  itself  (Fig.  157,  A  and  B).  The 
zygospore  thus  formed  is  set  free  by  the  decay  of  the  dead 


234  HOT  ANY. 

cell-walls  of  the  old  filament  surrounding  it ;  it  then  falls  to 
the  bottom  of  the  water  and  there  remains  until  the  proper 
conditions  for  its  growth  appear. 

312. — The  conjugation  described  is  the  one  best  known  ; 
it  prevails  in  a  large  part  of  the  genus  mentioned.  There 
are  some  curious  modifications  of  the  process.  In  what  is 
called  genuflexous  conjugation  the  opposing  cells  of  parallel 
filaments  become  strongly  bent  back  so  as  to  form  an  angle 
at  their  central  points  ;  then  the  angles  approach  each  other 
and  fuse,  allowing  the  cell-contents  to  pass  over,  as  in  the 
other  case. 

Lateral  conjugation  takes  place  between  the  cells  of  the 
same  filament.  At  the  contiguous  ends  of  two  cells  tubular 
processes  are  pushed  out,  which,  meeting,  form  a  curved 
channel  from  one  cell  to  the  other.  Occasionally  there  ap- 
pears to  be  only  a  slight  enlargement  of  the  contiguous  ends 
of  the  cells,  and  this  is  followed  by  the  breaking  away  of  a 
portion  of  the  separating  wall.  These  cases  of  lateral  con- 
jugation show  that  the  cells  are,  to  a  great  extent,  to  be  re- 
garded as  independent  organisms,  and  that  the  conjugation 
is  primarily  the  union  of  two  cells,  instead  of  two  filaments. 

313. — The  germination  of  the  zygospore  is  a  simple  pro- 
cess. The  inner  mass  enlarges  and  bursts  the  outer  hard 
coat;  it  then  extends  into  a  columnar  or  club-shaped  mass, 
gradually  enlarging  upward  from  its  point  of  beginning ; 
after  a  while  a  transverse  partition  forms  in  it,  and  this 
is  followed  by  another  and  another,  until  an  extended  fila- 
ment is  formed. 

(a)  The  principal  genera  are  ISpirngyra,  in  which  the  chlorophyll 
bands  are  spirally  arranged  in  the  cells,  and  Zygnana,,  in  which  the 
chlorophyll  is  usually  arranged  in  a  stellate  manner.  Sixteen  species 
of  8/iir  gyrn  are  recorded  as  occurring  within  the  United  States,  and 
of  these  Sp.  Ion  fia' a  and  Sp.  quini'<a  are  the  most  common.  Of  Zyg- 
n  ma  hut  two  species  are  recorded  in  the  United  States,  and  only  one 
of  these,  Z.  i  xignt,  is  common. 

(6)  These  plants  may  be  found  at  any  time  in  ditches  and  streams, 
where  they  often  form  extensive  massi-s  of  green  felt  ;  but  it  is  only 
from  the  middle  to  near  the  end  of  sprinjj  that  they  can  be  found  in 
conjugation.  For  the  Northern  States  the  time  varies  from  April  to 
the  first  of  June  ;  in  the  Smith  it  is  of  course  much  earlier,  being  in 


MUCORINI.  235 

Florida  as  early  as  February.  In  searching  for  conjugating  specimens 
only  the  yellow  and  brown  masses  of  filaments  need  be  examined,  as 
the  process  never  takes  place  in  the  bright  green  ones. 

314. — In  the  genera  Mesocarpus  and  Pleurocarpus  the 
conjugation  is  slightly  different  from  that  described  above. 
The  conjugating  tube,  which  is  much  longer,  becomes  di- 
lated midway  between  the  two  filaments,  and  in  this  the 
contents  of  the  two  cells  unite  and  form  a  zygospore.  This 
difference  has  been  considered  by  some  botanists  to  be  of 
sufficient  importance  to  set  off  these  genera  in  a  group  allied 
to,  but  distinct  from,  the  Zygnemaceae.  When  they  are  so 
set  off  they  constitute  the  Mesocarpece  ;  but  it  is  altogether 
probable  that  they  are  to  be  considered  rather  as  a  subdivi- 
sion of  the  Zygnemaceae  than  as  a  distinct  order. 

Mesocarpus  scalaris  is  our  most  common  species.  In  general  appear- 
ance it  resembles  the  previously  mentioned  species,  but  its  chlorophyll 
is  not  so  regularly  arranged. 

315.— Order  Mucorini.  The  Moulds  are  saprophytic  and 
sometimes  parasitic  plants ;  they  are  composed  of  long 
branching  filaments  (kyphce),  which  always  form  a  more  or 
less  felted  mass,  the  mycelium  ;  when  first  formed  the  hyphae 
are  continuous,  but  afterward  septa  are  formed  in  them  at 
irregular  intervals.  The  protoplasmic  contents  of  the  hy- 
phae are  more  or  less  granular,  but  they  never  develop  chlo- 
rophyll. The  cell-walls  are  colorless,  except  in  the  fruiting 
hyphae,  which  are  usually  dark  colored  or  smoky  (fuliginous). 
The  mycelium  sometimes  develops  exclusively  in  the  inte- 
rior of  the  nutrient  medium  ;  in  other  cases  it  develops 
partly  in  the  medium  and  partly  in  the  air.  In  some  species 
the*  mycelium, may  occasionally  attach  itself  to  the  hyphae 
of  other  plants  of  the  same  order,  and  even  to  nearly  related 
species,  and  derive  nourishment  parasitically  from  them.  It 
is  doubtful,  however,  whether  any  Moulds  are  entirely  para- 
sitic, and  so  far  as  parasitism  occurs  it  appears  to  be  con- 
fined to  narrow  limits  ;  none,  so  far  as  known,  are  parasitic 
upon  higher  plants. 

316. — The  reproduction  of  Moulds  is  asexual  and  sexual. 
In  the  asexual  reproduction  the  mycelium  sends  up  erect 


236 


BOTANY. 


hyphae,  which  produce  few  or  many  separable  reproductive 
cells — the  spores  (Fig.  158).  The  method  of  formation  of 
the  spores  in  Mucor  Mucedo  is  as  follows  :  the  vertical  hy- 
phai,  whicti  are  filled  with  protoplasm,  become  enlarged  at 

the  top,  and  in  each 
a  transverse  partition 
forms  (A,  a,  Fig.  159), 
the  portion  above  the 
partition  (b,  Fig.  159) 
becomes  larger,  and, 
at  the  same  time,  the 
transverse  partition 
arches  up  (B,  «,  Fig. 
159),  finally  appearing 
like  an  extension  of 
the  hypha,  then  called 

Fig.  158.-Diagram  showing  the  mode  of  growth  the  Columella  (C,  a, 
of  Mucor  Mucedo.  m,  the  mycelium:  g,  single  TTirr  1  ^\  Thp  nrr» 
sporangium,  borne  on  an  aerial  erect  hypha.-After  r  J&'  1  °  J>" 

Prantl-  toplasm    in     the    en- 

larged terminal  cell  (b)  divides  into  a  large  number  of 
minute  masses,  each  of  which  surrounds  itself  with  a  cell- 
wall  ;  these  little  cells  are  the  spores,  and  the  large  mother- 
cell  is  now  a  sporangium. 

In  the  other  Moulds  the  process  is  essentially  like  that 
in  Mucor  Mucedo.  In 
many  cases  there  are  sev- 
eral sporangia  formed  at 
the  top  of  the  vertical 
hyphae ;  in  such  cases  the 
latter  are  branched  before 
the  formation  of  sporan- 
gia. Another  variation 
from  the  method  as  de- 
scribed above  is  that  111  5l,  very  youn-r  stage  -~B.  somewhat  later;  C. 
,  eporanu'intn  with  npr  Mporen.  a  in  all  the  ng- 

SOme  SpeCieS  but  One  Spore     ures  represents  the  partition  wall  between 

»  -j    •  v  last  cell  of  the  filament  s 

is  formed  in  each  sporan- 


and  the  sporangium  b. 


gium  ;    the  hyphae   then   appear   to   bear  naked  spores. 

317.  —  The  spores  are  set  free  in  different  ways  ;  in  some 
cases  the  wall  of  the  sporangium  is  cnlircly  absorbed  by  the 
time  the  spores  are  mature  ;  in  other  cases  only  portions  of 


MUCORINI. 


23? 


the  sporangium-wall  are  absorbed,  producing  fissures  of  va- 
rious kinds — e.g.,  at  the  base  in  Pilobolus  ;  about  the  middle 
in  Circinella ;  irregular  in  Mucor,  etc.  The  spores  germi- 
nate readily  when  on  or  in  a  substance  capable  of  nourishing 
them  (but  not  in  pure  water)  ;  they  send  out  one  or  two  hy- 
phae  (sometimes  one  from  each  end),  which  soon  branch  and 
give  rise  to  a  mycelium.  Spores  may,  if  kept  dry,  retain 
their  vitality  for  months. 

318. — A  second  kind  of  asexual  formation  of  spores  takes 
place  in  some,  if  not  all,  the  genera  of  the  Mucorini.     The 


Fig.  160.— Conjugation  of  Mucor  »tolonifer.  a,  two  hyphse  near  each  other,  and 
fending  out  short  lateral  processes  or  branches,  which  come  in  contact ;  b,  the 
branches  grown  larger  ;  c,  the  formation  of  a  partition  near  the  end  of  oach  branch  ; 
d,  absorption  of  the  wall  between  the  two  branches,  and  the  consequent  union  of 
the  protoplasm  of  the  end  cells;  e,  zygospore  fully  formed,  e  X  90;  the  others 
nearly  the  same. — After  De  Bary. 

protoplasm  in  certain  parts  of  the  hyphse  condenses  and  b^- 
comes  transformed  into  single  reproductive  bodies,  known  as 
rfilamydospores.  Occasionally  they  form  at  the  ends  of 
hyphae,  arid  are  then  apt  to  be  mistaken  for  the  "fruiting" 
of  other  fungi. 

319. — Sexual  reproduction  takes  place  after  the  produc- 
tion of  asexual  spores  ;  the  mycelium  produces  at  particular 
points,  in  the  air  or  within  the  nutritive  medium,  two  simi- 
lar branches,  which  come  in  contact  with  each  other,  and  by 
fusing  their  contents  give  rise  to  a  zygospore  (Fig.  160). 


238  BOTANY. 

The  steps  in  the  process  in  Afucor  stolonifer  are  briefly  as 
follows  :  two  hyphae  come  near  each  other,  and  send  out 
small  branches,  which  come  in  contact  with  each  other  (a, 
Fig.  160)  ;  these  elongate  and  become  club-shaped,  and  at 
the  same  time  they  become  more  closely  united  to  each  other 
at  their  larger  extremities  (J,  Fig.  160);  a  little  later  a  trans- 
verse partition  forms  in  each  at  a  little  distance  from  their 
place  of  union  (c,  Fig.  160)  ;  the  wall  separating  the  new 
terminal  cells  is  now  absorbed,  and  their  protoplasmic  con- 
tents unite  into  one  common  mass  (d.  Fig.  160) ;  the  last 
stage  of  the  process  is  the  secretion  of  a  thick  wall  around 
the  new  mass,  thus  forming  a  zygospore  (e,  Fig.  160,  and  z, 
Fig.  161). 

It  is  interesting  and  instructive  to  note  here  the  close  simi- 
larity between  the  zygospore  of  Mucor  stolonifer  and  that  of 
Mesocarpus,  briefly  described  above  (par.  314).  In  both  the 
zygospore  is  formed  in  the  lateral 
branches  of  the  ordinary  filaments. 
320. — In  PiptocepJialis  the  for- 
mation of  the  zygospore  is  essen- 
tially like  that  in  Mucor,  with 
some  minor  differences.  The 
uniting  hypha-branches  are  large 
and  curved,  and  are  smaller  at 
their  points  of  union  ;  the  zygo- 
ig  lei  — Zygospore  e  of  MU-  spore  is  formed  at  first  in  the 

;  m,  mycelium.  -AfW  Prantl.       gmall  ne(jk  f ormed  by  the  union  of 

the  tips  of  the  branches,  but  it  soon  grows  so  much  as  to 
appear  to  be  external  (Z,  Fig.  162).  In  this,  as  \\\  all  other 
cases,  however,  the  zygospore  is  strictly  an  endogenous  for- 
mation. 

"  The  zygospore  does  not  germinate  until  it  has  under- 
gone desiccation,  and  has  experienced  a  certain  period  of 
rest,"*  when,  if  placed  in  a  moist  atmosphere,  it  sends  out 
hyphae  which  bear  sporangia.  The  zygospoivs  appear  never 

*  "Researches  on  the  Mucorini,"  by  Ph.  Van  Tieghem  and  Q.  Le 
Monnier  (translated  in  Quarterly  Journal  cf  Mwrofifopwal  Science, 
1874,  p.  49),  upon  which  most  of  what  is  here  said  about  the  Moulds  is 
baswi. 


MUCORINI. 


239 


to    form   a  mycelium ;    that  is   always  the   result  of  the 
growth  of  spores  from  the  sporangia. 

(a)  In  the  study  of  the  Moulds  it  is  almost  always  necessary  to  mako 
use  of  alcohol  for  freeing  the  specimens  of  air  ;  afterward  they  usually 


Fig.  l&t.—Piptocephalis  Frexeniana,  parasitic  upon  the  hyphse,  M,  M,  M,  of  Mucm 
Miicedo.  m,  m,  parasitic  hyphie,  attached  to  their  host  by  the  haustoria,  h  ;  e,  conid- 
ial  spores ;  s, «,  the  two  branches  which  conjugate  and  form  the  zygospore,  Z.  Highly 
magnified.—  After  Brefeld. 

require  to  be  treated  with  a  dilute  alkali,  as  a  weak  solution  of  am- 
monia or  potassic  hydrate,  which  causes  the  hyphae  to  swell  up  to  their 
original  proportions  before  drying  ;  care  must  be  taken  that  the  hyphae 
and  spores  are  not  unduly  swollen,  or  serious  mistakes  may  be  made. 

(6)  In  the  careful  study  of  the  Moulds  it  is  necessary  to  resort  to  arti- 
ficial cultures  of  the  different  species,  in  order  to  be  able  to  follow  them 


240  BOTANY. 

through  all  their  changes.  The  spore  of  a  particular  species  must  be 
sown,  and  the  development  of  hyphae,  mycelium,  sporangia,  etc.,  care- 
fully followed  ;  and  the  greatest  care  must  be  taken  to  guard  against 
error  from  the  accidental  presence  of  other  species. 

(c)  "Pan  culture,"  which  consists  in  sowing  the  spores  upon  or  in  the 
nutritive  medium  in  pans  or  deep  plates  covered  by  bell-jars,  must  always 
be  resorted  to,  even  if  more  accurate  cultures  are  also  made.     By  placing 
a  quantity  of  horse-dung  in  a  pan  under  a  bell-jar,  there  will  soon  be 
obtained  a  good  supply  of  vigorous  Moulds  ;  sometimes  several  species 
may  be  obtained  from  a  single  pan.     By  care  a  few  sporangia  of  each 
species  may  be  obtained  from  this  first  culture,  with  little  probability 
of  contamination  with  other  species.     These  are  to  be  used  for  more 
careful  cultures. 

(d)  If  now  moistened  pieces  of  fresh  bread  are  placed  under  a  bell- 
jar,  and  a  few  of  the  spores  of  a  particular  species  are  sown  on  them, 
the  growth  and  successive  stages  of  development  may  be  easily  fol- 
lowed.    Instead   of  bread,  other  materials   may    be  used,  as  stewed 
prunes  and  other  fruits,  pieces  of  oranges  or  lemons,  etc.,  and  for  cer- 
tain species  the  half-cleaned  bones  of  beef  from  the  kitchen. 

(e)  Where  still  greater  care  is  desirable,  the  nutritive  media  may  be 
prepared  by  boiling  and  filtering,  after  which  they  are  placed  in  thor- 
oughly cleaned  pans  or  plates,  and  covered  by  clean  bell-jars  ;  in  these 
are  placed  pieces  of  hardened  plaster  of  Paris  or  earthenware  (porous), 
which  have  previously  been  heated  so  as  to  destroy  all  spores,  and  upon 
them  are  sown  the  selected  spores.     The  sources  of  error  are  in  this 
way  very  much  reduced,  but  it  must  be  borne  in  mind  that  they  are  by 
no  means  all  eliminated  ;  hence  the  student  must  be  constantly  on  the 
lookout  for  other  species  than  the  one  under  culture. 

(/)  The  media  recommended  by  Van  Tieghem  and  Le  Monnier  are. 
(1ft)  boiled  and  filtered  orange  juice,  which,  being  acid  and  saccharine, 
is  not  so  liable  to  be  invaded  by  other  common  Moulds  ;  (2d)  a  decoc- 
tion of  horse  dung,  boiled  and  filtered  ;  this  is  neutral  and  alkaline,  and 
serves  as  a  medium  for  many  species  ;  but  it  is  open  to  the  objection 
that  it  is  liable  to  the  invasion  of  intruding  species  ;  (3d)  a  saline  sola- 
tion  of  the  following  composition  : 

Calcium  nitrate 4  parts. 

Potassium  phosphate. 1     " 

Magnesium  sulphate 1     " 

Potassium  nitrate 1     " 

Distilled  water 700     " 

[Sugar 7  parts.] 

In  some  cases  the  sugar  may  be  omitted. 

(g)  The  most  accurate  and  satisfactory,  but  at  the  same  time  most 
difficult  cultures,  are  cell-cultures.  These  aro  made  as  follows:  glass, 
tin,  or  India-rubber  rings  four  to  five  millimetres  high  are  fastened  to 


MUCORINI.  241 

ordinary  glass  slides  ;  a  very  little  water  is  placed  in  the  bottom  of  the 
cell  so  formed,  to  keep  the  air  in  it  always  moist ;  a  small  drop  of  the 
nutrient  liquid,  free  from  spores  of  any  kind,  is  placed  in  the  middle  of 
a  cover-glass  of  the  proper  dimensions,  and  in  this  a  single  spore  of 
some  particular  Mould  is  placed  ;  the  cover-glass  is  now  inverted  over 
the  cell,  and  held  in  place  by  a  minute  quantity  of  oil  on  the  edge  of 
the  cell.  The  preparation  must  be  placed  in  a  warm  and  saturated 
atmosphere.  An  ordinary  bell-jar  set  over  a  plate  of  water,  or  better 
still,  of  wet  sand,  will  furnish  a  very  good  moist  chamber.  The  appa- 
ratus used  by  Van  Tieghem  and  Le  Monnier  is,  however,  in  many  re- 
spects the  best  that  has  yet  been  devised  (Fig.  163). 

By  means  of  such  cultures  as  this,  the  student  may  follow  all  the  de- 
tails of  the  germination,  and  after-development  of  any  particular 
spore,  as  all  that  is  necessary  to  do  is  to  remove  the  slide  from  the 
growing  box,  and,  without  disturbing  the  cell,  to  place  it  under  the 
microscope  ;  the  same  specimen  may  thus  be  examined  any  number 
of  times,  with  the  least  possible  liability  of  error. 

(h)  The  most  common  Moulds  are  species  of  the  genus  Afucw.     ^f. 


Fig.  163.— Section  of  apparatus  for  cell  cultures.  The  shaded  portion  represents  a 
section  of  a  tin  or  zinc  box  :  a,  a,  the  supporting  ledges  ;  b.  It,  the  glass  slips  ;  c,  c, 
glass  or  uietal  rings  fastened  to  the  glas*s  slips,  seen  in  section,  and  covered  with  a 
piece  of  thin  glass  :  g,  plate  of  glass,  covering  the  box.  The  dotted  line  shows  the 
height  of  the  moist  sand  with  which  the  bottom  of  the  box  is  covered. 


Mucedo  and  M.  stt/lonifer  (if  distinct)  are  common  on  many  decaying 
substances.  M.  Syzygites  occurs  on  decaying  Agarics  and  Polypori. 
Pildbolus  crystvllinus,  Piptocephalis  Freseniina,  and  Chcetodadium 
Jonesii  occur  on  animal  excrement.  Phycomyces  nitens  grows  on  oily  or 
greasy  substances,  as  old  bones,  oil  casks,  etc. 

(t)  The  Moulds  are  evidently  related  to  the  Mesocarpeae  in  their 
sexual  reproduction,  which  is  the  most  important,  as  it  is  the  most  con- 
stant. The  conidia  of  Moulds  are  clearly  homologous  with  the  zoospores, 
of  the  Zoosporeae,  being  nothing  more  than  aerial  modifications  of  them. 
The  non-septated  condition  of  the  filaments  of  the  Moiilds  does  not  con- 
stitute so  great  a  difference  between  them  and  the  filaments  of  the  green 
Con jugatae  as  might  at  first  be  imagined;  in  the  germination  of  the 
zygospore  of  Spirogyra  it  will  be  remembered  that  the  filament  elon- 
gates quite  a  good  deal  before  a  septum  forms  in  it ;  between  this  and 
the  very  late  formation  of  septa,  as  in  the  Moulds,  the  difference  is 
only  one  of  degree.  The  Moulds  may  then  be  looked  upon  as  Meso- 
carpous  Conjugatas  which  have  lost  their  chlorophyll  through  their 
saprophytic  habits,  and  which  have  otherwise  undergone  slight  modifi- 
cations mainly  correlated  with  their  aerial  habits. 


242 


BOTANY. 


Fossil  ZygOSporeae.— Comparatively  few  species  of  Zygosporeae 
occur  in  a  fossil  state.  Tlie  oldest  known  is  a  Jurassic  species  of  Con- 
fervites,  a  genus  which  is  also  represented  by  a  few  species  in  the  Ter- 
tiary. Fossil  Diatoms  of  many  species  have  been  found  in  the  Tertiary  ; 
at  Richmond,  Va.,  they  form  a  vast  bed,  nearly  ten  metres  thick,  and 
one  at  Monterey,  California,  is  sixteen  metres  in  thickness. 


ARRANGEMENT  OF  THE  CLASSES  AND  ORDERS  OF  ZYQOSPORE^B. 


CONJUGATE. 


ZOOSPORB^C. 


CHAPTER    XVI. 

OOSPORE^E. 

321. — The  distinguishing  feature  of  the  plants  belonging 
to  this  division  is  that  they  develop  a  large  cell  (the  oogo- 
nium),  differing  from  those  about  it  in  size  and  general  ap- 
pearance, which  contains  one  or  more  rounded  masses  of 
protoplasm  (the  oospheres),  which  are  subsequently  fertilized 
by  the  contents  of  a  second  kind  of  special  cell  of  much 
smaller  size  (the  anther idium).  The  oogonium  is  the  fe- 
male reproductive  organ,  and  the  antheridium  the  male. 
The  protoplasm  of  the  latter  is  in  some  cases  transferred  by 
direct  contact  to  the  oosphere  ;  in  other  cases  it  is  first  broken 
up  into  motile  bodies,  the  spermatozoids,  which  then  come 
to  and  become  fused  with  the  oosphere.  The  oosphere  itself 
is  never  motile,  and  in  most  cases  it  remains  within  the 
parent  plant  until  long  after  it  is  fertilized.  The  result  of 
fertilization  is  the  production  of  an  oospore,  which  differs 
from  the  oosphere  structurally  in  having  a  hard  and  gener- 
ally colored  coating,  and  physiologically  in  having  the  power 
of  germination  and  growth  after  a  period  of  rest  of  greater 
or  less  duration. 

322. — The  plants  of  this  division  vary  greatly  as  to  the 
development  of  the  plant-body.  In  some  cases  it  is  a  feebly 
united  colony  ( Volvox  and  its  allies),  while  in  its  highest 
forms  it  is  a  well-developed  thallus,  with  even  the  beginning 
of  a  differentiation  into  Caulome,  Phyllome,  and  Boot 
(Fucacem). 

§  I.  VOLVOX  AND  ITS  ALLIES. 

323. — In  the  classification  of  the  plants  of  this  division 
the  lowest  place  must  be  assigned  to  Volvox  and  Eudorina, 
which,  as  previously  stated,  are,  with  doubtful  propriety, 


244  BOTANY. 

separated  from  Pandorina.  If  the  two  genera  are  to  be 
separated  from  Pandorina  there  can  be  but  little  doubt  that 
their  position  must  be  in  the  very  lowest  part  of  the  Oospo- 
reae.  Such  a  position  would  indicate  what  is  probable  on 
other  grounds  also,  that  the  divisions  Zygosporeae  and  Oospo- 
reae  lie  side  by  side  as  two  divergent  systems,  and  that  in 
their  lowest  members  they  almost,  if  not  entirely,  coalesce.* 
324. —  Volvox  globator  is  a  hollow  spherical  colony  of  uni- 
cellular algae,  having  a  diameter  of  .5  to  .8  mm  (.02  to  .03 
inch).  Each  individual  of  the  colony  is  a  flask-shaped  cell 
of  green-colored  protoplasm,  bearing  two  cilia  upon  its 
pointed  extremity,  and  surrounded  by  a  hyaline  gelatinous 
envelope.  These  individuals  are  arranged  so  as  to  form  a 
spherical  surface,  their  hyaline  envelopes  being  in  contact 
with  one  another,  and  so  placed  as  to  bring  the  pointed  ends 
of  the  green  masses,  with  their 
cilia,  to  the  surface.  The 
sphere  is  thus  made  up  of 
closely  approximated  individ- 
uals, which  dot  its  surface, 
and  whose  cilia  give  to  the 
whole  colony  a  hairy  appear- 
ance. The  movements  of  the 

164.-  voivox  giot>at<»:  a,  sperma-  cilia  give  to  the  sphere  a  ro- 
^^  taiy  motion,  which  is  usually 

one  of  progression  also. 

325. — The  sexual  reproduction  of  Volvox  takes  place  in 
this  way  :  some  of  the  cells  in  a  colony  undergo  conversion 
into  spermatozoids,  which  are  elongated  club-shaped,  and 
provided  with  two  cilia  («,  Fig.  164) ;  other  cells  of  the  same 
colony,  or  of  different  colonies,  become  greatly  enlarged  into 
oogonia,  consisting  of  an  outer  hyaline  coat  enclosing  an 
inner  rounded  mass  of  dense  and  granular  protoplasm  (b,  Fig. 
164).  Upon  the  escape  of  the  spermatozoids  they  penetrate 
the  cavity  of  the  colony  (into  which  the  oogonia  have  now 
pushed),  and  there  coming  in  contact  with  the  oogonia,  they 

*  It  will  not  do  violence  to  any  laws  of  classification,  based  upon 
the  general  theory  of  evolution,  to  propose  that  Volo&x,  Eudorina, 


VOLVOX  AND  ITS  ALLIES. 


245 


bury  themselves  in  the  hyaline  envelope,  and  finally  pene- 

trate and  become  fused  into  the  oosphere  (b,  Fig.  164).      A 

thick  wall  now  forms  upon  the  fertilized  oosphere,  and  it 

becomes  transformed  into  an  oospore.      Thus  we  have  in 

these  plants  the  transformation  of  an 

individual  of  the  colony  into  an  oogo- 

nium  and  oosphere,  and  the  subse- 

quent fertilization  of  the  latter  by 

spermatozoids,  which  are  themselves 

fractional  parts  of  other  members  of 

the  colony. 

326.  —  The  relationship  of  the  low- 
er Oosporeae  with  the  lower  Zygo- 
sporeae,  as  indicated  by  Volvox  and 
Pandorina,  is  further  shown  by  the 
position  of  Sphceroplea,  an  undoubted 
relative  of  the  Confervacece  (Clado- 
phora,  etc.).  Sphceroplea  is  a  free, 
unbranched,  filamentous  alga,  com- 
posed of  long  cells  joined  end  to  end 
(A,  Fig.  165).  It  produces  oospheres 
in  some  of  its  filaments,  each  cell 
producing  several  (B,  Fig.  165). 
While  these  are  forming  in  one  set  of 
filaments,  in  another  the  protoplasm  oogoma;  m  and  k,  oospneres 

,       ,  .     ,  if-i     i       it  the  instant  of  fertilization  ; 

becomes  broken  up  into  a  multitude  «,  fertilized  oospb.  res,  now 

of  elongated,  bi-ciliate  spermatozoids 

(O  and  0,  Fig.  165);  these  escape 

through  lateral  openings  in  the  cells,  °^nlj?tf  t0n?ck 

which  are  formed  by  the  absorption  lose'  -f,.zoospore  (vegetiih-e 

,.  J        .   ,.  V  .  zoogonidium).    f,  oosphere  in 

Of  a  part  of  the  Wall,  and  then  SWim-    the  act  of  being  fertilized  by  a 
11  t       ii  11  Q      -,    spermatozoid,  «.    G.  spermato- 

ming  through   the  water  they  find  zoids.  -After  (Ersted. 
their   way  to  corresponding  openings   in  the  walls  of   the 

and  their  allies  in  the  Oosporeae,  and  Pandorina,  and  its  allies  in  the 
Zygosporeae,  be  placed  in  a  common  class  Zoosporeae.  This  class 
would  thus  have  two  branches,  one  in  the  division  Zyjfosporeae,  and 
the  other  in  the  Oosporeae.  Such  an  arrangement  would  indicate 
the  evident  relationship  of  the  plants  under  consideration  better  than 
any  yet  proposed. 


246  BOTANY. 

cells,  which  contain  the  oospheres  ;  upon  coming  in  contact 
with  an  oosphere  they  bury  themselves  in  its  substance,  after 
which  the  oosphere  secretes  a  thick  wall,  and  thus  becomes 
an  oospore(Z),  Fig.  165).  In  germination  (which  takes  place 
after  a  period  of  rest)  the  protoplasmic  contents  of  the 
oospore  become  broken  up  into  a  large  number  of  bi-ciliated 
zoospores  having  nearly  the  shape  and  general  appearance 
of  the  spermatozoids  ;  these,  after  swimming  about  for  a 
time,  become  gradually  elongated  into  narrowly  fusiform 
filaments,  which  are  the  young  Splmroplea  individuals  ;  In- 
growth these  take  on  the  form  and  size  of  the  adult  indi- 
viduals. 

§  II.  CLASS  (EDOGONIE^E. 

327. — The  plants  constituting  this  well-marked  class  are 
composed  of  articulated,  simple,  or  branched  filaments, 
which  are  attached  to  sticks,  stones,  earth,  or  other  objects 
by  root-like  projections  of  the  basal  cells.  The  chlorophyll 
in  the  cells  is  always  dense  and  uniform.  They  inhabit 
ponds  and  slow  streams,  and  form  green  masses,  which  fringe 
the  sticks  and  other  objects  in  the  water. 

328. — r'  he  (Edogoniese  are  interesting  for  the  well-marked 
examples  they  afford  of  the  intercalary  growth  of  cells.  It 
is  commonly  the  case  that  in  any  filament  at  one  or  two 
points  there  may  be  seen  near  one  end  of  a  cell  a  number 
of  transverse  parallel  lines,  which  in  profile  have  the  appear- 
ance of  as  many  caps  slipped  into  one  another  (C,  Fig.  10, 
page  22) ;  these  are  the  results  of  several  extensions,  of  the 
filaments  by  intercalary  growth.  The  process  is  as  follows  : 
in  a  cell,  a  little  below  its  upper  wall,  a  growth  inward  from 
the  surface  of  the  wall  takes  place  in  such  ;i  way  as  to  form 
a  cylindrical  ring  (A,f,  Fig.  10);  after  a  time  the  cell-wall 
splits  circularly  from  the  outside  to  the  centre  of  the  circu- 
lar cylinder  (/),  and  the  two  parts  of  the  cell  then  retreat 
from  each  other,  united  only  by  the  straightened  out  cylin- 
der (B,  z,  Fig.  10);  this  new  part  elongates  and  the  process 
is  repeated,  finally  giving  rise  to  the  series  of  caps  first  men- 
tioned (C,  c,  Fig.  10),  and,  in  conjunction  with  cell-division, 
resulting  in  a  considerable  elongation  of  the  filaments. 


CEDOOONIE^E. 


247 


B 


329. — The  asexual  reproduction  of  (Edogonieae  is  as  curi- 
ous as  the  growth  of  its  cells,  just  described.  During  the 
early  and  active  growth  of  the 
plants  the  protoplasmic  contents  of 
certain  cells  in  a  filament  become 
detached  from  their  walls,  and  upon 
the  splitting  of  the  latter  the  now 
rounded  protoplasm  escapes  as  a 
large  zoospore  (Fig.  166,  A  and 
B} ;  it  is  oval  in  shape,  and  provid- 
ed with  a  crown  of  cilia  about  its 
smaller  hyaline  end,  by  means  of 
which  it  swims  rapidly  hither  and 
thither  in  the  water  (Fig.  166,  0). 
After  a  time  it  comes  to  rest, 
clothes  itself  with  a  cell-wall,  and 
sends  out  from  its  smaller  end  root- 
like  prolongations  (Fig.  166,  Z)), 
which  attach  it  to  some  object ;  it 
now  elongates,  and  at  length  forms 
partitions,  taking  on  eventually  the 
form  of  the  adult  filament.  It 
sometimes  happens  that  before  the 
new  plant  resulting  from  the 
growth  of  a  zoospore  has  formed  its 
first  partition,  the  protoplasm  sep- 
arates from  its  wall  and  again  aban- 
dons it,  to  be  for  a  time  a  zoospore 
(Fig.  166,  E}.  This  method  of 
formation  of  zoospores  is 
Braun  called  Rejuvenescence.  (See  withdrawn 

>  preparatory  to  escaping.    B,  es- 

1).  42.)  cape  of  protoplasm  and  formation 

nnn        nil  i  j       ,L •  of  a  zoospore ;  the  hyaline  por- 

330. —  1  he    Sexual    reproduction  tion  of  the  latter  is  » t-en  to  be  lat- 


reproduc- 
A,  fracture 

•lament  and  escape  of  the 
protoplasm  of  the  broken  cell ; 
•nrVio-r     the  protoplasm  in  the  whole  cell 
'u    below  is  seen  to    be   somewhat 
from    the    cell-wall, 


of  the  plants  of  this  class  is  in 
many  respects  closely  allied  to  that 
of  Spliceroplea.  The  female  organs 
are  in  all  cases  developed  in  essen- 
tially the  same  way,  but  the  male 
organs  present  a  considerable  diversity. 


oral.  G,  a  ciliated  and  swimming 
zoospore,  thi-  hyaline  portion  now 
terminal.  D,  zoospore  at  rest, 
and  sending  out  root  like  pro- 


The  female  organ 


248 


BOTANY. 


consists  of  a  rounded  oosphere  situated  within  a  cavity — the 
oogonium  ;  it  is  developed  from  one  of  the  cells  (sometimes 

two)  of  the  filament 
by  a  condensing 
and  rounding  off 
of  the  protoplas- 
mic contents;  when 
the  oosphere  is  ful- 
ly formed,  an  open- 
ing is  formed  in 
the  oogonium-wall 
for  the  ingress  of 
the  spermatozoids 
(A  and  B,  Fig. 
167).  One  or  more 
spermatozoids  are 
produced  in  each  of 
certain  small  cells 
which  are  formed 
from  the  large  ones 
by  a  process  of 
simple  fission ;  in 
shape  they  resem- 
ble the  zoospores 
mentioned  above — 
that  is,  they  are 
oval  and  provided 
with  a  crown  of 

Fig.  167—^4,  middle  part  of  a  t-eximl  filament  of  CEdo-  yibratile     cilia      Oil 
gonium  clliatum  (Amlio(i>/nia  of  Wood),  with  male  cellfl 

above  at  m;  og,  oogonia  ^fertilized)  ;    HI,  dwarf  male  their     Smaller      6X- 

plants  attached  to  the  side  of  the  oogonia,  the  spenna-  -,        /  n 

tozoids  already  dischanred.      X  260.    B,  oogonium,  og,  tremity    (JJ,      Z,     Z, 
at  the  moment  of  fertilization  ;  o.  the  oosphere  ;  «,  the 


at  the  moment  of  fertilization  ;  o.  the  oosphere  ;  z,  the  rp-          -.  Rn\         TTr»rm 

gpermatozoid  forcing  its  way  into  the  oosphere ;  m.  the  r  Ig-     AU<;«        U£IUU 

dwarf  male  plant.      O,  ripe  oospore.     />.   (Edogonium  nar>f\\\\t\ct     infr»    flio 

f/emtllip'irumd'rin^hnmin^  VVood),  part  of  the  male  C.-Caplllg     mtO    tne 

filament,  with  Hpermatozoids,  u,  issuing  from  the  cells.  w-lfpr  which  is  reil- 

/;.  pr.rt  of  a  branch  of  Bulbocha-tt  intermedia,  with  oojro-  "  ^ter,  WI 

nia,  the  uppermost  containing  nn  oospore,  the  middle  dei'ed     possible     by 

one  with  an  oospore  escaping,  the  lower  empty,    /'.four  \                       J 

zooopores  resulting  from  an  oospore  of  Bv4bocha>te.     G,  a    Spllttmo;    of    the 

Koospore  come  to  rest  and  germinating.— After  Priugs-  *     ,    .    °           . 

heim  wall  of  the  mother- 
cell,  they  swim  about  vigorously,  and  eventually  make  their 
way  through  the  opening  in  the  oogonium,  and  then  bury 


(EDOGONIEJS.  249 

themselves  in  the  substance  of  the  oosphere  (B,  z,  Fig.  167). 
After  fertilization  the  oosphere  becomes  covered  with  a  thick 
and  colored  (brown  or  red)  coat,  and  it  then  becomes  an 
oospore  (C,  Fig.  167). 

331. — In  certain  cases  the  cells  which  produce  the  sper- 
matozoids  occur  on  the  same  filaments  which  produce 
oogonia  also  ;  this  is  the  monoecious  type.  In  other  cases  one 
of  the  ordinary  cells  of  the  filament  which  bears  oogonia  be- 
comes divided  by  simple  fission  into  two  or  more  cells  ;  the 
protoplasm  in  each  of  these  new  cells  condenses  into  an 
ovate  mass,  which  by  a  rupture  of  the  cell-wall  is  set  free  as 
a  motile  body  resembling  a  small  zoospore,  and,  like  it,  pro- 
vided with  a  crown  of  vibrating  cilia;  this  is  the  androspore. 
After  swimming  about  for  some  time,  it  comes  to  rest  upon, 
or  near  to,  an  oogonium,  and  attaches  itself  by  root-like  pro- 
jections, exactly  as  in  the  case  of  the  growth  of  true  zoo- 
spores  ;  the  result  of  the  growth  of  the  androspore  is  the  pro- 
duction of  a  miniature  plant  composed  of  three  or  four  cells 
(A,  m,  m,  and  B,  m,  Fig.  167).  The  upper  cells  of  these 
little  plants  develop  spermatozoids,  and  hence  the  plants  are 
called  dwarf  males.  This  is  the  so-called  gynandrous  type 
(A  and  B,  Fig.  167).  In  a  third  class  of  cases,  the  ordinary 
plant  filaments  are  of  two  kinds,  the  one  producing  sperma- 
tozoids only,  and  the  other  only  oogonia  ;  this  is  the  dioecious 
type  (D,  Fig.  167). 

332. — After  a  period  of  rest  the  oospore  germinates  by 
rupturing  its  thick  coat,  and  permitting  the  escape  of  the 
contents,  enclosed  in  a  thin  envelope  ;  by  this  time  the  pro- 
toplasm has  divided  into  four  portions,  which  take  on  an 
oval  form,  and  develop  a  crown  of  cilia  (F,  Fig.  167).  They 
soon  escape  from  the  investing  membrane,  and  after  a  brief 
period  of  activity  groAV  into  an  ordinary  filament  in  exactly 
the  same  manner  as  the  zoospores. 

(a)  It  will  be  unnecessary  iu  this  place  to  fully  discuss  the  arrange- 
ment of  the  genera  belonging  to  this  class  ;  they  probably  may  be  all 
brought  within  the  limits  of  one  order  coextensive  with  the  class. 
Wood  has  separated*  two  sub-families  (=  sub-orders),  which  differ  in 

*  "  A  Contribution  to  the  History  of  the  Fresh-water  Algae  of  the 
United  States,"  by  H.  C.  Wood,  1872, 


250  BOTANY. 

the  filaments  in  the  one  case  ( Bulbochcete)  being  branched  and  terminated 
with  setae,  while  in  the  other  case  ((Edogonium  and  its  allies)  the  fila- 
ments are  not  branched,  and  are  destitute  of  true  setae. 

(6)  The  old  genus  (Edogonium  is  divided  by  Wood  into  three  new 
genera,  as  follows  : 

Monfficious  :  antheridia  and  oogonia  upon  the  same  individual — 

(Edogonium. 
Difficious  :  antheridia  and  oogonia  arising  upon  distinct  individuals 

— Priiigsheimia. 
Gynandrous :  antheridia  upon  dwarf  plants,  growing  attached  to 

the  female  plant — Aiidrogynia. 

We  have  no  known  representatives  of  the  first  in  the  United  States  ; 
of  the  second  Wood  records  one  species,  P.  inequaM*,  which  is  closely 
allied  to  P.  gemeUiparum  (D,  Fig.  167)  ;  of  the  tliird  genus  we  have 
four  species,  of  which  A.  muHispora  and  A.  mirabilis  are  the  most 
common. 

(c)  The  genus  Bulbochcete  includes  gynandrous  species,  of  which 
there  are  three  recorded  in  the  United  States  ;  the  most  common  is  B. 
iynota. 

§   III.     CLASS   C(ELOBL ASTERS. 

333.— In  the  plants  of  this  class  the  protoplasm  is  con- 
tinuous throughout  the  vegetative  organs  of  the  plant,  and 
is  not  divided  into  cells.  Only  the  reproductive  organs  are 
separated  by  partitions.  They  may  hence  be  spoken  of  as 
unicellular,  although  they  often  attain  a  considerable  length 
and  are  frequently  much  branched. 

The  other  characters  of  the  group  will  be  best  understood 
from  a  study  of  some  of  the  plants  included  in  it.  Many  of 
them  are  chlorophyll-bearing  plants,  living  in  brooks  and 
streams,  while  others  are  destitute  of  chlorophyll,  and  are 
saprophytes,  living  upon  decaying  animal  or  vegetable  matter, 
or  are  parasites,  living  upon  the  living  tissues  of  the  higher 
plants. 

334. — The  genus  Vaucheria  may  be  taken  as  a  represen- 
tative of  the  chlorophyll-bearing  members  of  this  class.  It 
is  a  filamentous  alga  growing  in  water  or  on  damp  earth,  and 
forming  dark  green  tufts.  Each  plant  consists  of  long, 
branching,  thick-walled  tubes,  which  have  a  rather  large 
diameter ;  they  are  attached  to  the  earth,  or  to  sticks  or 


(JfBLOB  LASTED. 


251 


other  objects,  by  root-like  processes  (w,  Fig.  168).  The 
protoplasmic  contents  of  the  tubes,  which  are  destitute  of  a 
nucleus,  consist  of  a  thick  green  layer  upon  the  inner  sur- 
face of  the  wall,  leaving  the  centre  of  the  tubes  open  for  the 
more  watery  portions. 

335.—  The  asexual  reproduction  of  Vaucheria  presents 
some  considerable  variations  ;  it  consists  essentially  of  a 
spontaneous  separation  of  a  portion  of  the  protoplasm  of  the 
parent  plant.  In  some  species  this  takes  place  by  the  sepa- 


Pig.  168.—  Vaucheria  sessilis.  A,  end  of  a  branch,  with  escape  of  a  zoospore,  sp.  B, 
zoospore  in  its  res-ting  stage,  after  the  disappearance  of  its  cilia.  G,  the  same,  germi 
<iating.  D,  the  same,  further  advanced.  Jff,  much  later  stage  of  germination  ;  sp,  the 
zoospore;  w  the  root-like  processes  irhizoids).  F,  fertile  plant;  og,  og,  oogonia  fer- 
tilized ;  A,  an  old  antheridium.  x  30  —After  Sachs. 

ration  of  swollen  lateral  branches,  which  then  send  out  fila- 
ments ;  in  other  species  the  protoplasm  in  the  swollen  lateral 
branch  becomes  separated  from  that  in  the  general  cavity  of 
the  plant  by  a  septum,  and  it  afterward  condenses  into  a 
rounded  mass  and  acquires  a  wall  of  its  own  ;  it  is  set  free 
by  the  decomposition  of  the  old  surrounding  wall,  and  it 
germinates  by  sending  out  one  or  two  tubes,  which  grow 


252  BOTANY. 

directly  into  now  plants.  In  still  other  species  the  spore 
forms  us  in  the  lust  case,  but  there  is  a  dehiscence  of  the  sur- 
rounding wall  which  permits  the  spore  to  slip  out ;  it  begins 
to  germinate  soon.  In  some  species,  instead  of  forming  a 
spore,  the  naked  protoplasm  in  the  swollen  branches,  after 
condensing  somewhat,  escapes  into  the  water  through  a 
fissure  in  the  cell-wall,  and  becomes  a  zoospore  (A,  Fig. 
168) ;  it  is  covered  throughout  its  whole  surface  with  delicate 
vibrutile  cilia,  by  means  of  which  it  moves  through  the 
Avater  (Fig.  169).  After  a  short  period  of  activity  the  zoo- 
spores  come  to  rest,  their  cilia  disappear,  and  a  wall  of  cellu- 
lose is  formed  (B,  Fig.  168) ;  in  this  condi- 
tion  (the  zoogonidium)  they  remain  for  some 
hours,  when  they  begin  to  germinate  by 
sending  out  one  or  two  tubes  (C,  D,  Fig. 
168) ;  the  root-like  organs  grow  either  direct- 
ly from  the  zoogonidium  (F,  Fig.  168),  or 
from  one  of  the  tubes  (E,  Fig.  168). 

336. — Sexual  reproduction  takes  place  in 
lateral  branches  also.     Both   antheridia  and 
oogonia  develop  as  lateral  protuberances  upon 
the   main  stem  (og,  og,  h,  Fig.   168).     They 
vwKhe-  originate  as  diverticula  of  the  principal  cavity 
a,  ecto-  (4   oq,  h,  Fig.  170)  ;  these  develop  on  the  one 

plasm  bearing    the    v         ,* 

cilia  ;&,  endophism.    hand    into   male   organs,  and   on   the  other 

X  eOO.-Osmic  acid     .     ,       ,  .  mi  •      i 

preparation,  after  mto  female  organs.  The  male  organ  is  long 
and  rather  narrow,  and  soon  much  curved 
(B,  0,  Fig.  170)  ;  its  upper  portion  becomes  cut  off  by  a 
partition,  and  in  it  very  small  bi-ciliate  spermatozoids  (I), 
Fig.  170)  are  developed  in  great  numbers.  The  female  or- 
pin is  short  and  ovoid  in  outline,  and  usually  stands  near 
the  male  organs.  In  it  a  partition  forms  near  its  point  of 
union  with  the  main  stem  ;  the  upper  portion  becomes  an 
oogonium,  and  its  protoplasm  condenses  into  a  rounded 
body,  the  oosphere  (6vand  E,  Fig.  170)  ;  at  this  time  the 
wall  of  the  oogon in m  opens,  and  permits  the  entrance  of  the 
spermatozoids  which  were  set  free  by  the  rupture  of  the 
antheridium-wall.  Upon  coming  into  contact  with  ^he 
oosphere  the  spermatozoids  mingle  with  it  and  disappotir  ;  the 


CCKLOB LASTED. 


253 


oosphere  immediately  begins  to  secrete  a  wall  of  cellulose 
about  itself,  and  it  thus  becomes  an  oospore  (F,  Fig.  170). 
According  to  Pringsheim,  the  oospore  remains  for  three 
months  in  a  resting  state  before  germinating  ;  in  the  latter 
process  the  outer  coat  of  the  spore  splits,  and  through  the 
opening  a  tube  grows  out  which  eventually  assumes  the  form 
:ind  dimensions  of  the  full-grown  plant. 


the  oogonium  (oft) 
same,  the  antheridium  (a 
titioti.    C.  an  open  oo<ron 
ppermatnxoida  collected 


Fig.  170.— Sexual  o-ga      of  Vaucheria  MutiH*.     A,  beginning  of  the  formation  of 


theri 'inm  (h)  upon  the  hranr-h  b.  B.  later  stage  of  the 
io\v  separated  from  the  main  branch  (b)  by  a  transverse  par- 
m  expelling  a  drop  of  mucilage,  si.  D,  epermatozoids.  &', 


the  mouth  of  the'oogoninm.  F.  the  nntheridium,  a,  col- 
apsed after  the  escape  of  the  ppemmto/oids  ;  osp,  the  oospore.  x  about  100,  except 
I),  which  is  much  more.—  C,  D,  after  Pringsheini,  the  others  after  Sachs. 

(a)  The  formation  of  zonspores  begins  in  the  night,  they  escape  in 
the  morning,  and  the  night  following  they  germinate. 

(6)  The  formation  of  sexual  organs  begins  in  the  evening,  and  is 
completed  the  next  morning  ;  fertilization  takes  place  during  the  day 
(from  10  A.M.  to  4  P.M.). 

(c)  Good  specimens  of  Vaucheria  may  be  found  clothing  the  boggy 
ground  about  many  springs.  The  bright  green  mats  may  be  trans- 
ferred to  the  aquarium  for  the  study  of  zoospores  ;  but  for  the  sexual 
organs  the  dingy  and  dirty  looking  specimens  must  be  collected. 


254  ROTANY. 

(d)  The  genus  Vaucherui  may  be  taken  as  the  type  of  a  group,  the 
Vaucheriacea ,  but  whether  it  is  entitled  to  rank  as  an  order  instead 
of  a  family  cannot  be  decided  in  this  place.  Allied  to  Vaucheria  are 
Vaulerpa,  Hnlimeda,  etc. ,  but  their  exact  position  is  as  yet  problematical. 

(e)  Van  heria  includes  in  the  United  States  the  species  V.  seftsilis 
and  V.  polymorpha,  which  are  common  in  fresh  water,  besides  some 
others  not  so  frequently  seen,  some  of  which  inhabit  salt  water. 

(y)  Caulerpites  cact  idea  is  the  oldest  known  fossil  species  of  this 
class.  It  occurs  in  the  Silurian  :  other  species  have  been  detected  in 
the  Devonian  and  Tertiary.  Caulerpa  extends  from  the  Tertiary  to 
the  present. 

337.— Order  Saprolegniacese.  The  plants  of  this  order 
are  saprophytes  or  parasites,  more  frequently  the  latter ;  they 
are. colorless,  and  generally  are  to  be  found  in  the  water  or  in 
connection  with  moist  tissues.  The  plant-body  is  greatly 
elongated  and  branched,  and  all  its  vegetative  portion  is 
continuous — i.e.,  unicellular;  the  reproductive  portions  only 
are  separated  from  the  rest  of  the  plant-body  by  partitions. 

338. — The  reproduction  is  very  much  the  same  as  in 
Vaucheria,  and,  as  in  that  genus,  is  of  two  kinds — asexual 
and  sexual.  The  asexual  reproduction  may  be  briefly  de- 
scribed as  follows  :  the  protoplasm  in  the  end  of  a  branch 
becomes  somewhat  condensed,  a  septum  forms,  cutting  off 
this  portion  from  the  remainder  of  the  filament,  and  the 
whole  of  its  contents  becomes  converted  by  internal  cell- 
division  into  zoospores  provided  with  one  or  two  cilia 
(Fig.  171,  1).  These  soon  escape  from  a  fissure  in  the  wall 
and  are  active  for  a  few  minutes  (3-4),  after  which  they 
come  to  rest  and  their  cilia  disappear  (2  and  3,  Fig.  171). 
In  one  or  two  hours  they  germinate  by  sending  out  a  filament 
(4,  Fig.  171),  from  which  a  new  plant  is  quickly  produced.* 

330. — The  sexual  organs  bear  a  close  resemblance  to  those 
of  Vaucheria.  The  oogonia  are  spherical,  or  nearly  so  (in 
most  of  the  species),  and  contain  from  two  to  many  oospheres, 
which  are  fertilized  by  means  of  antheridia,  which  usu:ill\ 
develop  as  lateral  branches  just  below  the  oogonia.  In 

*  The  student  is  referred  to  an  article,  "Observations  on  Several 
Forms  of  Saprolegniese,"  byF.  B.  Hine,  in  American  Quarterly  Micro- 
scopical Journal,  1878,  p.  18,  from  which  some  of  the  above  facts  are 
taken,  and  the  accompanying  figures  adapted. 


SAPOLEGNIA  CE^ti. 


255 


some  species  the  antheridia  and  oogonia  are  upon  the  same 
plants,  and  in  such  cases  the  fertilization  takes  place  by  the 


Fig.  171. — 1,  end  of  filament  of  Saprolrgnia  with  zoosport-s  (swarm-spores)  escap- 
ing :  2,  zoospores  of  the  same  at  rest ;  3,  the  same  more  enlarged  ;  4.  the  same, 
germinating :  5,  a  portion  of  a  filament  of  Aehl>  a,  bearing  sexual  organs,  x  120  :  6, 
first  stage  in  th  •.  development  of  sexual  organs  of  Acfilya  ;  7.  8,  9.  succeeding  siages  ; 
10,  sexual  organs  of  5,  more  enlarged,  showing  the  anrheridia,  jind  the  nearly  ripe 
oogonium,  with  its  contained  oospores.— Adapted  from  Hine. 

direct  contact  of  the  antheridium  and  the  passage  of  its 
contents  into  the  oogonium  by  means  of  a  tubular  process 


256 


BOTANY. 


from  the  former  ;  in  other  species  the  plants  ;ire  dioecious, 
and  in  them  the  antheridia  produce  motile  Bpennatozoidts,  by 
means  of  which  the  fertilization  is  effected.  After  fertilization 
each  oosphere  becomes  covered  with  a  wall  of  cellulose  and 
is  thus  transformed  into  an  oospore. 

340. — The  development  of  the  sexual  organs  of  Aclilya, 
one  of  the  genera  of  this  order,  is  shown  in  Fig.  171,  6  to 
10  ;  at  first  there  is  a  small  pullulation  upon  the  side  of  a 
filament,  as  at  6  ;  this  soon  extends  into  a  bag-like  projec- 
tion (7),  which  is  readily  seen  to  be  a  young  oogonium ; 
it  continues  to  enlarge,  while  its  protoplasm  becomes  more 
dense,  and  at  its  narrower 
part  a  second  pullulation 
forms  (frequently  two),  as 
shown  at  8  ;  when  the  larger 
part  has  enlarged  somewhat 
more  and  become  rounded,  a 
partition  separates  it  from 
the  remainder  of  the  filament, 
and  from  the  young  anther- 
idium,  as  shown  at  9  ;  the 
protoplasm  in  the  oogonium 
forms  several  round  masses — 
the  oospheres — and  by  this 
time  the  terminal  portion  of 
the  antheridium  is  cut  off  by 
a  partition.  In  the  monoe- 
cious species  a  tube  is  formed  by  the  closely  applied  anther- 
idium, which  penetrates  into  the  oogonium  through  open- 
ings in  it  formed  by  the  absorption  of  portions  of  its  wall 
and  comes  in  contact  with  one  of  the  oospheres  (Fig.  172). 

341. — In  some  cases,  instead  of  the  oogonia  developing 
in  the  way  described  above,  they  are  formed  in  the  terminal 
part  of  a  filament  by  one  or  more  partitions  arising  in  it  ; 
such  oogonia  are  cylindrical  or  barrel-shaped,  and  sometimes 
several  of  them  stand  upon  one  another.^  The  antheridia  in 
the  species  which  have  such  oogonia  are  developed  from 
below  the  partition  which  cuts  off  the  oogonium,  and  when 
then-  arc  several  .superimposed  oogonia  it  actually  happens 


Fig.  ire.— F.  rtilix-ntionof  theoo.-pheres 
in  AcUya  racemona.  Each  oogoniimi 
contains  two  oospheres.  Magnified.— 
Aftur  Cornu. 


8APROL  EONIA  CB^. 


that  the  antheridia  which  fertilize  one  oogonium  grow  out 
of  the  oogonium  lying  immediately  beneath.*  In  this  case 
it  appears  that  the  terminal  oogouium  is  formed  first,  and 
that  the  antheridia,  in  each  case,  grow  out  from  what  is  yet 
a  part  of  the  whole  filament,  and  that  it  is  only  subsequently 
to  the  formation  of  antheridia  that  an  oogonium  is  formed 
out  of  that  part  of  the  filament  out  of  which  they  grew.  In 
the  accompanying  diagram  (Fig.  173)  the  ' 
oogonium  a  is  fertilized  by  antheridia 
which  grew  out  of  that  portion  of  the 
filament  which  subsequently  became  cut 
off  as  oogonium  b,  which  in  turn  is  fer- 
tilized by  antheridia  from  below  it,  and  so 
on  to  d,  which  receives  its  antheridia 
from  what  still  remains  as  part  of  the  fil- 
ament. Each  oogonium  is  seen  to  be 
younger  than  the  one  above  it — in  other 
words,  the  oogonia  are  developed  from 
the  top  of  the  filament  downward. 

The  oospores  of  Saprolegniaceae  possess, 
when  mature,  a  thick  integument,  which 
is  double — that    is,  formed   of  an  outer 
thicker  coat  (epispore)  and  an  inner  thin-  of 
nerone(endospore).    After  a  considerable 


Fig.  173.— Diagram  il- 
lustrating the  formation 
the    sexual    organs 


period  of  repose  the  oospores  germinate  wh^^Nfertiifzed"^ 


by  sending  out  a  tube,  f 

The  Saprolegniaceae  have  been  but  little  stud-  0|jn  eroo^oninm  with 

ied  in  this  country,  although  they  may  be  read-  the  oocplieres   not  yet 

ily  obtained.       They   grow   quickly    upon   dead  e"t  ^xcmimn ;  theUhu- 

fishes,  crayfishes,  flies,  etc.,  when  placed  in  tanks  ter  wilF  be  fertilized  by 

of  water,  and  may  often  be   seen  attached  para-  grow  outfrom'fhe  upper 

sitically  to  young  living  fishes  in  aquaria.     They  j-'nd  of  the  filament  be- 
are  often  so  abundant  in  the  breeding-houses  of 
fishes  as  to  cause  great  losses.     In  some  of  the  rivers  in  England  dur- 


*  The  student  should  consult,  an  article  on  "  Two  New  Species  of 
Saprolegniese,"  etc.,  in  Qr.  Jour.  Mic.  Science,  1867,  p  121,  in  which 
figures  and  a  description  of  such  a  form  as  that  above  referred  to  are 
given. 

f  See  De  Bary's"  Morphologic  und  Physiologic  derPilze,"  etc.,  1866, 
p.  155,  for  an  account  of  the  sexual  reproduction  of  Saprolegniaceae, 


253 


BOTANY. 


ing  the  year  1878,  and  for  a  year  or  two  previous  to  that  date,  large 
numbers  of  salmon  and  other  kinds  of  fish  were  destroyed  by  one  of  the 
common  species,  Saprolegniaferax.* 

342.— Order  Peronosporeee.  The  plants  of  this  order 
live  parasitically  in  the  interior  of  higher  plants.  They  are 
composed  of  long  branching  tubes,  whose  cavities  are  con- 
tinuous throughout.  They  grow  between  the  cells  of  their 
hosts,  and  draw  nourishment  from  them  by  means  of  pecu- 


FIG.  175. 


Fig.  174.— A  vegetative  hypha,  m,  m,  of  Peronotpora  calotheca  from  the  tissue  of 
Asj)eriiln  tativa.  The  two  cells  between  t  e  are  filled  with  the  long  branching  haus- 
toria  from  the  hvpha  m.  m.  X  390. — After  De  Bary. 

Fijr.  175.-Conidia-b       ' 
first  conidia  upon  the 

third  <  onidia  ;  the  pedicel  is  proliferous  from  the  base  of  each  conidium  after  it  is 
formed,  and  thus  the  conidia,  which  are  actually  terminal,  come  to  appear  lateral. 
X  200.-After  De  Bary. 


lia-bearing  hyphW  of  Peronosponi  infeatans.    a,  formation  of  the 
i  the  ends  of  slender  pedicels  ;  b,  the  formation  of  the  second  and 


liarly  formed  lateral  branches  (haustoria),  which  thrust 
themselves  through  their  walls  (Fig.  174,  and  Fig.  176,  A,  h). 
The  vegetative  growth  is  entirely  within  the  host,  and  also 

and  a  translation  in  "  Grevillen,"  Vol.  I.,  p.  117.  See  also  Prings- 
heim's  "  Jahrbucher  fur  Wissenschaftliclie  Botanik,"  Vol.  IX.,  p.  289, 
and  Max  Cornu,  in  "  Annales  des  Sciences  Naturelles,"  5e  ser.,  torn. 
XV. 

*  See  a  description  by  W.  G.  Smith  in  "  Grevillea,"  Vol.  VI.,  1878, 
p.  152. 


PERO&O3POIUE. 


259 


the  sexual  organs  ;  the  asexual  reproductive  organs,  on  the 
contrary,  are  on  the  surface  of  the  host. 

343. — The  asexual  reproduction  takes  place  in  the  genus 


.&' 


w  f 


Fig.  176. — Cysiopus  candidw.  A,  branch  of  mycelium,  f,  growing  at  the  apex,  £, 
and  giving  off  haustoria,  h,  into  the  cells  of  the  pith  of  Lepidium  sativum.  B,  co- 
nidia-bearing  porti  >m  of  the  mycelium,  with  conidia  in  rows.  C,  a  conidium  with 
its  protoplasm  divided.  Z>,  contents  of  conidia  escaping  as  swarm-spores  (zoospores). 
E,  8warm-sj)circs  (zoospores),  with  cilia.  F,  germinating  swarm-spores.  G,  two  swarm- 
spores,  up,  germinating  on  a  stoma  and  penetrating  it.  //,  a  swarm-spore,  sp,  of  the 
potato  disease  (  I'IT >iu><i>ar<i  vifi^uix)  penetrating'  the  epidermis  of  the  potato  stem; 
e,  i,  epidermis  cells.  X  400.— After  De  Bary. 

Peronospora  by  the  mycelium  inside  the  host  producing 
branches,  which  protrude  through  the  stomata  into  the  air  ; 
here  their  tips  become  enlarged,  and  finally  separated  by  par- 
titions from  the  remaining  parts  of  the  hyphas,  thus  forming 


260  BOTANJ. 

the  conidia  (Fig.  175).  In  the  different  species  there  are 
considerable  variations  in  the  size  and  shape  of  the  conidia, 
and  the  mode  of  branching  of  the  conidial  hyphse,  and  upon 
these  many  specific  characters  are  based. 

344. — In  the  genus  Cystopus  the  formation  of  conidia  is 
slightly  different.  The  conidial  hypha?  multiply  greatly  at 
certain  points  beneath  the  epidermis  of  the  host,  and  there 
produce  couidia  by  successive  constrictions  (B,  Fig.  176). 
The  conidia  remain  in  loose  connection,  and  form  moniliform 
rows,  in  which  the  uppermost  conidium  is  the  oldest ;  some- 
times six  or  more  conidia  may  be  seen  attached  to  each  other 
in  this  way,  but  generally  the  upper  ones  soon  fall  away. 
When  the  epidermis  of  the  host  ruptures,  the  conidia  appear 
g  as  a  powdery  mass, 

which  may  be  blown 
away  by.  the  feeblest 
movement  of  the  air. 

345. — The  germina- 
tion of  conidia  presents 
two  modes :  in  some 
species  of  the  genus 

Fig.  177.— Germination  of  the  conidia  of  Perono-    £                             ,,     c 
siiora  infextans.    a,  conidium  after  lying  for  some   Pcronospord    the     CO11- 
time  in  water,  the  contents  divided;  b,  the  rupture    , ,         .    ,,          -j. 


time  in  water,  the  contents  divided  ;  6,  the  rupture    ,       ,         .   ,, 

of  the  conidium  and  the  escape  of  the  parts  as   tents   Ot   the 

swarm-ppores>  (zoospores) ;  c,  swarm-spores,  with       i         Til'ippd  nndpr   thp 

cilia  ;  d,  swarm-spores  after  coming  to  rest,  in  va-    v> 

rioiiBBtagesof  germination,  x  390.-Af ter  De  Bary.    proj)cr      conditions      of 

moisture  and  temperature,  become  transformed  into  many 
bi-ciliate  swarm-spores  (a,  1),  and  c,  Fig.  177).  These  are 
active  for  a  time,  after  which  they  come  to  rest,  their  cilia 
disappear,  and  a  germinating  tube  is  sent  out  from  each 
(d,  Fig.  177),  which,  if  properly  situated,  enters  a  stoma. 
and  in  the  interior  of  its  host  gives  rise  to  a  system  of  vege- 
tating hyphae  ;  in  other  cases  it  perforates  the  epidermis  cell- 
walls  and  thus  passes  into  the  interior  of  its  host  (H,  Fig. 
176).  In  other  species  of  Peronospora  the  conidium  does  not 
break  up  into  swarm-spores,  but  gives  rise  directly  to  a  ger- 
minating filament.  In  all  the  species  of  the  genus  Cystopus, 
the  conidia  first  give  rise  to  swarm-spores  (C,  D,  E,  F,  G, 
Fig.  176),  in  the  manner  dcscrilx'tl  above  for  l'er(int>x/>»r«. 


PERONOSPORE^. 


261 


346. — In  the  sexual  reproduction,*  which,  us  above  stated, 
eitways  takes  place  in  the  intercellular  spaces  of  the  host, 
lateral  branches  of  two  kinds  arise  upon  the  hyphae ;  those 
of  the  one  kind,  the  young  oogonia,  become  greatly  thickened 


Fig.  178. — The  sexual  organs  and  fertilization  of  Peronospora  Alfineaiiim.  a, 
youngest  stage  ;  o.  young  oogonium  ;  «,  young  antherulinm  ;  b.  the  same  somewhat 
later  ;  the  anthericiium  is  beginning  to  thrust  its  beak-like  process  (fertilizing  tube) 
into  the  oogonium  ;  <j,  the  same  at  a  still  later  stage— the  fertilizing  tube  has  reached 
the  oosphere.  x  350.  —Alter  De  Bary. 

in  diameter,  and  finally  assume  a  globular  shape  ;  their 
highly  granular  protoplasm  becomes  condensed,  and  finally 
separated  from  that  of  the  remainder  of  the  filament  by  a 
transverse  septum  at  the  base  of  each  oogonium  (a,  Fig.  178). 
The  other  branches,  the  young  anthe- 
ridia,  which  arise  upon  the  same  fila- 
ments as  the  oogonia  and  near  to 
them,  or  upon  other  filaments  which 
are  in  proximity  to  the  oogonia-bear- 
ing  ones,  become  elongated  and  club- 
shaped  ;  their  protoplasm  (also  gran- 
ular) becomes  condensed  in  their  up- 
per  portions,  which  are  soon  separated 
from  the  rest  of  the  filament  by  a 
transverse  partition  in  each  case  (a,  int«  contact  with  the  oo- 

v         sphere.     Much   magnified.— 
Fig.     178).         At    this    Stage    the    an-    After  De  Bary. 

theridia  become  applied   to  the  oogonia,  and  in   each  of 
the  latter  the  protoplasm  has  still  further  condensed  and 

*  Consult  De  Bary's  "  Morphologic  und  Pliysiolojrie  der  Pilze,"etc., 
pp.  158-159,  a  translation  of  which  appeared  in  "  Grevillea,"  1873,  p. 
150. 


262 


BOTA  V )'. 


rounded  into  an  oosphcrc.  Each  antlieridiuin  now  devel- 
ops a  tubular  beak-like  process,  which  penetrates  the  oogo- 
nium  (b,  Fig.  178),  and  finally  reaches  the  oospore  (c,  Fig. 
178,  and  Fig.  179).  It  appears  that  the  contents  of  the  an- 


Fig.  180. — Cystopns  candid-us.  A,  mycelium,  with  young  oogonia,  Off.  J5,  oogoni- 
um.  og  ;  on,  oospore ;  an,  antheridium.  0,  mature  oogomum,  r>(t,  with  oospore,  o.«; 
at  the  left  :s  the  le'imnnt  of  the  nntheridium.  D,  mature  oospore  M-'ii  in  section.  //. 
beginnins;  of  gei munition  of  oospore,  the  enclosporu  i  with  its  contents  escaping 
through  a  rent  in  the  epispore  tor  exospore).  F,  the  endosporo  i  filled  with  swarm- 
spores  (zoopporis1*  resting  on  the  empty  epispore.  G,  swarm-spores  (zoospores),  each 
with  two  cilia.  X  400.— After  De  Bary. 

theridium  pass  into  the  oosphere,  as  in  a  short  time  the 
former  is  found  to  be  empty,  while  the  latter  becomes  envel- 
oped in  a  cell-wall,  and  thus  becomes  an  oospore.  In  the 
process  of  fertilization  there  are  no  spcrmatozoids,  and  the 


PERONOSPORE^B.  2G3 

process  is  comparable  to  that  which  takes  place  among  the 
monoecious  Saprolegniaceas.  The  wall  of  the  oospore  be- 
comes differentiated  into  two  or  more  layers  (as,  in  fact,  is 
usual  in  resting  spores),  the  outer  of  which  (the  epispore}  is 
thick,  hard,  rough,  and  dark  colored,  while  the  inner  (the 
endospore}  is  thin  and  transparent  (C,  D,  E,  F,  Fig.  180). 

347. — In  their  sexual  reproduction  the  species  of  the  genus 
Cystopus  agree  with  those  of  Peronospora  above  described. 
The  various  stages  are  shown  in  Fig.  180. 

348. — The  germination  of  the  oospores  takes  place  in  some 
species  of  the  genus  Peronospora  by  the  formation  of  a  ger- 
minating tube,  which  soon  gives  rise  to  a  mycelium.  In 
Cystopus,  however,  the  oospore  swells,  and  by  the  bursting 
of  the  epispore  the  endospore  escapes  as  a  loose  bladder  sur- 
rounding the  protoplasm,  which  has  by  this  time  become  di- 
vided into  a  large  number  of  naked  masses  of  protoplasm 
(E,  F,  Fig.  180) ;  by  the  bursting  of  the  surrounding  mem- 
brane, these  bodies  are  set  free  as  bi-ciliate  swarm-spores  (G, 
Fig.  180),  which,  after  a  short  period  of  activity,  come  to 
rest,  and  germinate  in  exactly  the  same  way  as  those  derived 
from  the  conidia.  In  some  species  of  Peronospora  it  appears 
that  swarm-spores  are  developed  as  in  Cystopiis,  and  it  ap- 
pears from  the  observations  of  W.  G.  Smith,  that  in  the  potato 
fungus  (Peronospora  infestans)  some  of  the  oospores  pro- 
duce swarm-spores,  while  others  send  out  a  germinating 
tube.* 

349. — But  little  is  known  regarding  the  time,  as  well  as 
the  mode  of  germination  of  the  oospores,  but  from  those  ob- 
served it  is  probable  that  it  takes  place  after  a  period  of  rest 
extending  from  autumn  to  spring.  This  is  known  to  be  the 
case  in  some  species  of  Cystopus,  in  which  the  oospores  pass 
the  winter  in  the  rotting  tissues  of  its  hosts. 


•*  See  a  paper  "  On  the  Germination  of  the  Resting  Spores  of  Perono- 
spora  Infestans,"  by  Worthington  G.  Smith,  in  Gardeners'  Chronicle, 
July,  1876,  and  reprinted  in  "  Grevillea,"  1876,  p.  18.  He  found  that  the 
oospores  which  germinated  first  produced  swarm-spores  like  those  of 
Cystopus,  while  the  later  ones  "  protrud<  d  a  thick  and  generally  jointed 
thread."  In  his  account  figures  of  both  modes  are  given. 


264  BOTANY. 

(a)  The  plants  of  this  order  are  easily  obtained,  and  so  far  as  their 
structure  is  concerned,  are  easily  studied.     Their  development  is,  how- 
ever, much  more  difficult  to  follow,  and  in  some  species  it  has  thus  far 
baffled  the  most  skilled  botanists.     The  two  genera  Peronospora  and 
Cystopus  are  distinguished  by  their  conidia,  which  in  the  first  are  ter- 
minal and  single  upon  branches  of  the  aerial  hyphse  (Fig.  175),  while 
in  the  second  they  are  in  moniliform  rows  upon  hyphse  which  burst 
through  the  epidermis  of  the  host  (B,  Fig.  176). 

(b)  Several  species  of  Peronospora  are  very  easily  obtained.     P.  viti- 
cola,  the  American  grape  mildew,  is  common  on  the  leaves  and  young 
shoots  of  the  grape  ;  from  it  may  be  obtained  in  midsummer  an  abun- 
dance  of  conidia  and  conidial  hyphse,  and   in   autumn  (Ociober)  the 
oospores  may  be  found  in  abundance  in  the  dried  and  shrivelled  parts  of 
the  affected  leaves.*   P.  parasitica  is  common  in  spring  and  early  sum- 
mer, on  Cruciferae,  especially  on  L'pidium,  Capsella,  Drdba,  etc.,  fre- 
quently clothing  the  leaves  with  a  white,  frost-like  down.   P.  infestans, 
the  potato  fungus,  is  common  in  many  parts  of  the  country  on  the 
leaves  and  stems  of  the  potato,  sometimes  causing  great  injury  by  de- 
stroying the  leaves,  stems,  and  even  the  tubers.     Other  species  occur 
on  Eupatorium,  Bidens,  Ambrosia,  Impatiens,  Potentilla,  Anemone, 
etc. 

(c)  The  species  of  Cystopus  which  are  most  common  are  C.  candidus, 
which  may  be  found  in  the  spring  and  summer  as  white,  blister-like 
blotches  on  the  leaves  of  Capsella  and  other  Cruciferae  ;  and  C.  Bliti  com- 
mon on  Portulaca  oleracea  and  species  of  Amarantus  in  summer  and 
autumn  ;  the  latter  is  an  excellent  species  to  study,  as  its  oospores  are 
very  easily  found,  especially  in  the  stems  of  Portulaca. 

(d)  In  preparing  specimens  for  the  study  of  the  sexual  organs,  small 
portions  of  the  tissues  containing  them  should  be  boiled  for  a  minute 
or  so  in  a  solution  of  potash,  and  then,  while  the  preparation  is  hot,  a 
considerable  quantity  of  acetic  acid  should  be  added  ;  the  effervescence 
which  follows  separates  the  softened  tissues  so  that  but  little  difficulty 
is  experienced  in  isolating  large  portions  of  the  mycelium  with  oogonia 
and  antheridia.    It  frequently  happens  that  the  parts  are  rendered 
more  distinct  by  the  addition  of  iodine  to  the  specimen  after  mounting 


§  IV.    CLASS 

350.  —  The  plants  of  this  class,  composed  of  marine  spe- 
cies, present,  in  most  cases,  a  development  of  the  plant-body 
which  is  unusually  perfect  for  the  Thallophytes.  In  many 

*  For  the  best  account  of  this  fungus  see  a  paper  "  On  the  American 
Grape-vine  Mildew,"  by  Professor  W.  G.  Farlow,  in  Bulletin  of  the 
Bussey  Institution,  Vol.  I.,  p.  415.  Several  other  species  are  also  briefly 
described. 


FUCACEJt.  265 

cases  there  is  a  differentiation  of  the  thallus  into  parts  which 
have  a  considerable  resemblance  to  roots,  stems,  and  leaves  ; 
and  in  size  they  approach,  and,  in  some  cases,  equal  or  exceed 
the  larger  Phanerogams.  Their  tissues,  too,  show  a  much 
higher  degree  of  differentiation  than  is  common  in  Thallo- 
phytes  ;  the  cells  are  arranged  in  cell-masses,  and  these  are 
differentiated  into  several  varieties  of  parenchyma,  approach- 
ing, in  some  instances,  to  the  condition  which  prevails  in 
the  Bryophytes  ;  the  outer  tissues  are  composed  of  small  and 
closely  crowded  cells,  which  form  a  dense,  and,  in  some  cases, 
a  hard  mass ;  the  interior  tissues  are  generally  looser,  and 
are  for  the  most  part  composed  of  elongated  cells  so  joined 
as  to  leave  large  intercellular  spaces. 

351. — With  the  foregoing  there  is  found  in  the  higher 
genera  a  marked  differentiation  of  portions  of  the  plant- 
body  into  general  reproductive  organs,  analogous  to  the 
floral  branches  of  higher  plants.  The  sexual  organs  are 
found  upon  modified  branches,  which  differ  more  or  less  in 
shape  and  appearance  from  the  ordinary  ones.  This  differ- 
entiation into  vegetative  and  reproductive  parts  is  an  impor- 
tant and  significant  feature  in  the  plant-body,  indicating  a 
decided  advance  over  all  the  previous  groups  of  Thallo- 
phytes. 

In  their  greater  duration  many  of  the  Fucacese  are  in 
marked  contrast  to  other  Thallophytes,  which  are  generally 
short-lived.  They  are,  for  the  most  part,  of  considerable 
size,  rivalling,  in  some  cases,  even  the  larger  Phanerogams. 
They  grow  principally  between  and  a  little  beyond  the  tide- 
marks,  and  furnish  the  great  bulk  of  the  shore  vegetation. 

352. — The  reproduction  of  the  higher  Fucacese  is  sexual 
only ;  but  in  some  algae  which  appear  to  be  nearly  allied 
(Phseosporese)  asexual  zoospores  are  known.  In  Fucus 
the  sexual  organs  are  found  in  the  thickened  ends  of  the 
lateral  branches  of  the  thallus  (A,  Fig.  181).  They  occur 
on  the  "walls  of  hollows  termed  conceptacles,  which  are 
spherical,  with  a  small  opening  at  the  top  (B,  Fig.  181). 
The  conceptacles  are  at  first  portions  of  the  general  surface, 
which  afterward  become  depressions  which  are  walled  in 
and  overgrown  by  the  surrounding  tissues  ;  they  are  thus  to 


266 


BOTANY. 


be  still  regarded  as  portions  of  the  general  surface,  and  the 
cells  which  form  the  inner  surface  of  the  conceptacles  con- 
stitute a  continuation  of  the  epidermal  tissue  of  the  thallus. 
353. — The  walls  of  the  conceptacles  are  clothed  with 
pointed  hairs,  which  in  some  species  project  through  the 


Fig.  lS\.—Jfwc>tsplatycarnug.  A,  end  of  a  portion  of  thallns  ;  /,/,  conceptacles  In 
fertile  branchleis.  B,  vertical  section  through  a  conceptacle  ;  «,  hnirs  projecting 
from  the  month  :  b,  cavity  of  conceptaele  nearly  tilled  with  hairs  ;  e,  uogonia  ;  e,  an- 
theridia;  rf,  epidermal  tissue  of  thallus.— After  Thuret. 

opening,  and  among  these  are  found  the  sexual  organs, 
which  are  themselves,  as  Sachs  has  pointed  out,  modified 
hairs.  Some  of  the  species  are  monoecious,  while  others  are 
dioecious.  In  the  monoecious  species  the  antheridia  and 
oogonia  occupy  the  same  conceptacle  (B,  Fig.  181)  ;  the 
antheridia  are  produced  as  lateral  branches  of  modified  hairs 


FUCACE^E. 


267 


(A,  Fig.  182) ;  each  antheridium  is  a  thin-walled  cell,  whose 
protoplasm  breaks  up  into  a  large  number  of  bi-ciliate  sper- 
matozoids, which  escape  by  the  rupture  of  the  surrounding  wall 
(B,  Fig.  182).  Before  rupturing,  however,  the  antheridia 
detach  themselves  and  float  in  the  water  with  their  contained 
spermatozoids. 

354. — The  oogonia  are  globular  or  ovoid  short-stalked 
bodies,  which  develop  from  papillae  on  the  wall  of  the  con- 
ceptacle.  As  each  papilla  elongates,  it  becomes  divided  into 


Fig.  182.—  Fucus  vesicuiosus.  A,  branched  hair  bearing  antheridia,  a.  B,  sperma- 
tozoids. /.,  Off,  oogonium.  with  contents  divided  into  eight  parts  ;  ;;,  paraphyses,  or 
surrounding  hairs.  //.,  commencement  of  the  escape  of  the,  oospheres— the  outer 
wall,  a,  of  the  oogonium  has  burst,  the  inner,  i,  is  ready  to  open.  ///.,  oosphere  es- 
caped, and  surrounded  by  r-permatozoidl ;  IV.,  F.,  germination  of  the  oospore.  B 
X  330,  all  the  rest  1(50.  -  Alter  Thuret. 

u  basal  and  an  apical  portion  by  a  transverse  partition  ;  the 
upicul  part  enlarges,  and  (in  the  genus  under  consideration) 
its  protoplasm  divides  into  eight  portions  (/,  Fig.  182), 
which  eventually  become  spherical ;  it  is  thus  an  oogonium 
containing  eight  oospheres.  The  oospheres  escape  from  the 
oogonium  surrounded  by  an  investing  membrane,  which  floats 
out  through  the  opening  of  the  conceptacle,  where  it  finally 
ruptures  and  sets  the  oospheres  free  (II,  Fig.  182).  The 
spermatozoids  and  oospheres  are  liberated  at  about  the  same 


268  BOTANY. 

time,  and  the  former  gather  around  the  inactive  oospheres 
in  great  numbers,  and  by  the  vigor  of  their  movements 
sometimes  actually  give  them  a  rotatory  motion  (///,  Fig. 
182).  The  result  of  the  coming  together  of  the  spermato- 
zoids  and  the  oospheres  is  the  fertilization  of  the  latter,  and 
their  transformation  into  oospores  by  the  secretion  of  a  wall 
of  cellulose  on  each  one.  There  is  thus  seen  to  be  a  close 
similarity  between  the  fertilization  of  Fucus  and  of  other 
Oosporeae  ;  particularly  does  it  call  to  mind  the  sexual  pro- 
cess in  Volvox  and  its  allies.  When,  however,  the  sexual 
organs  proper,  and  their  accessory  organs,  the  conceptacles, 
are  taken  into  the  account,  the  relationship  of  Fucus  to  Volvox 
is  seen  to  be  much  less  than  it  appears  to  be  at  first  sight. 

355. — The  development  of  the  oospore  takes  place  at 
once ;  it  lengthens  and  undergoes  division  into  numerous 
ceils,  and  at  the  same  time  it  elongates  below  into  root-like 
processes,  which  serve  to  hold  fast  the  new  plant  (V,  IV, 
Fig.  182).  There  is  a  gap  in  our  knowledge  of  the  life- 
history  of  these  plants,  extending  from  the  young  thallns  to 
the  fertile  plant ;  probably  when  that  is  filled  some  plants 
now  supposed  to  be  distinct  will  be  found  to  be  forms  or 
stages  of  these. 

(a)  It  is  impossible,  with  our  present  knowledge  of  the  structure  of  ap- 
parently allied  groups,  to  determine  the  limits  of  this  class.     It  is  prob- 
able that  it  will  eventually  be  shown  to  include  most  of  the  orders 
usually  arranged  by  English  botanists  under  the  Melnnospeniiece  (the 
Fucoidece  of  Agardh) ;  should  this  surmise  prove  to  be  correct,  Agardh's 
name  should  be  applied  to  the  class  in  place  of  Fucacea,  which  should 
be  retained  for  the  order. 

(b)  The  PhcBogporece,  wliich  are  apparently  allied   to  the    Fucaceff, 
are  frequently  of  large  size  ;  they  are  often  flat,  strap-shaped  growths, 
as  In  Lnminaria,  of  several  metres  in  length  ;  in  other  cases  they  bear 
bladders  of  enormous  size  (two  metres  long),  ns  in  Nereocystis  ;  while 
in  Lessonia  they  assume  tree-like  forms,  sometimes  from  eight  to  ten 
metres  (25  to  30  feet)  in  height,  with  a  trunk  ten  to  twenty  centimetres 
(4  to  8  inches)  in  diameter.     Afacrocystis  produces  an  enormous  thallus 
sometimes  more  than  one  hundred  metres  long  (300  feet),  resembling, 
a  gigantic  pinnate  leaf,  which  floats  in  the  water  by  means  of  numer- 
ous air  bladders  ;  the  whole  is  attached  to  a  slender  stem,  one  to  two 
centimetres  thick. 

(e)  The  principal  genera  of  F'/cacece  are  Fucus  and  Sargassum.      Of 


PUCACSJB. 


269 


the  first,  F.  nodosus,  F.  fureatus,  and  F.  vesiculosus  are  the  most  com- 
mon species  on  our  Eastern  coast  ;  the  latter  also  occurs  on  the  Pacific 
coast;  both  are  known  as  Rock-weeds.  Sargasaum  vulgare  is  common 
on  the  Atlantic  coast ;  8.  bacciferum,  the  Gulf-weed,  is  found  in  the 
warmer  parts  of  the  several  oceans,  and  in  mid- Atlantic  covers  an  im- 
mense tract  known  as  the  Sargasso  Sea. 

(d)  The  species  of  Fucus  and  Sargassum  are  washed  ashore  in  great 
quantities  during  violent  storms,  constituting  the  bulk  of  the  "  wrack  " 
of  the  coasts.     They  furnish  valuable  manure  lor  enriching  the  soil, 
and  are  largely  used  for  this  purpose.     From  their  ashes  alkalies  and 
iodine  are  obtained.     From  the  hardened  stems  of  a  species  of  Lami- 
naria  walking-sticks,  whips,  knife  handles,  etc.,  are  manufactured. 

(e)  In  the  Silurian  period  Facoides  antiquus  represented  the  order 
Fucaceae,  while  Lamiiuirites,  Harlan>a,  etc.,  probably  represented  the 
Phseosporese.     In  the   Devonian  both   these  orders  were  abundantly 
represented.     Fucus,  Sargnxsum,  and  other  genera  were  already  in 
existence  during  Tertiary  times. 


AHHANGEMENT  OP  THK  CLASSES  AND  ORDERS  OF  THE  OOSPORE^E. 


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JLASTE^K. 

CHAPTER  XVII. 

CARPOSPOEE^E. 

356. — The  distinguishing  characteristic  of  the  plants 
which  constitute  this  vast  division  is  the  formation  of  a 
sporocarp,  as  a  result  of  the  fertilization  of  the  female  organ. 
The  sporocarp  consists,  except  in  the  simplest  cases,  of  two 
parts  essentially  different  from  each  other,  viz.,  (1)  a  fer- 
tile part,  which  either  directly  or  indirectly  produces  spores, 
sometimes  a  few,  or  even  one,  or,  on  the  other  hand,  a  very 
great  number ;  (2)  a  sterile  part,  consisting  of  cells  or  tis- 
sues developed  from  the  cells  adjacent  to  the  fertile  part, 
and  so  formed  as  to  envelop  it.  This  group  includes  plants 
with  chlorophyll,  and  a  large  number  of  species  which  are 
parasitic  or  saprophytic,  and  which,  as  a  consequence,  are 
destitute  of  chlorophyll.  In  the  former,  the  sporocarp  is 
small  in  proportion  to  the  size  of  the  vegetative  parts  of  the 
plant ;  but  in  the  latter,  where  the  vegetative  parts  are  great- 
ly reduced,  the  sporocarp  is  proportionately  large.  In  this 
the  parasites  and  saprophytes  of  the  Carposporeae  are  like 
those  of  the  Phanerogams,  in  which  the  vegetative  or  assimi- 
lative organs  are  smaller  than  in  those  which  contain  chlo- 
rophyll ;  thus  the  very  large  sporocarp  of  many  of  the  Asco- 
mycetes  and  the  Basidiomycetes,  and  their  relatively  small 
mycelium,  may  be  compared  to  the  large  reproductive  organs 
and  the  reduced  stems  and  leaves  of  the  Rafflesiacece.* 

*  This  comparison  must  not  be  misunderstood.  It  does  not  imply 
homology  of  the  parts  compared,  but  it  is  intended  to  compare  the 
vegetative  and  reproductive  organs  of  the  one  group  of  plants,  func- 
tionally considered,  with  those  of  the  other.  There  can  be  no  doubt 
that  functionally  the  giant  flower  of  liafflesin  is  the  equivalent  of  the 
sporocarp  of  a  Pezizu,  while  structurally  they  are  not  equivalent  ;  in 
other  words,  they  are  analogues,  but  not  homologues. 


271 

357. — The  female  organ  is  in  this  division  called  a  car- 
pogonium, which  consists  of  a  single  cell  (e.g.,  Coleochcete, 
some  Ascomycetes,  and  the  Characece),  or  of  several  cells  (e.g., 
Floridece  and  most  Ascomycetes).  In  some  cases  a  projec- 
tion, called  the  trichogyne,  is  attached  to  the  carpogoniutu  ; 
its  function  appears  to  be  the  conveyance  to  the  carpogonium 
of  the  fertilizing  influence  received  from  the  antheridium. 

358. — The  antheridium  is  here,  as  el.-ewhere  throughout 
the  Cryptogams,  much  more  variable  in  structure  than  the 
female  organ.  In  some  cases  it  is  applied  to  the  carpogo- 
nium in  fertilization,  while  in  others  it  produces  spermato- 
zoids  ;  in  either  case  contact  with  the  carpogonium  is  either 
direct  (Podosphcera,  Characece),  or  indirect,  through  a  tri- 
chogyne (e.g.,  Coleochcete,  Floridece,  Peziza). 

359. — The  plant-body  shows  in  general  a  more  perfect 
development  in  the  Carposporeaa  than  in  the  preceding  di- 
visions. While  it  is  but  little  developed  in  the  parasitic  and 
saprophytic  species,  it  is  well  developed  in  many  of  the  Flo- 
ridece and  the  Characece.  In  these  classes  there  is  often  a 
considerable  amount  of  differentiation  of  the  plant-body 
into  caulome  and  phyllome. 

§   I.    COLEOCHjETE. 

360. — The  genus  Coleochcete  maybe  taken  to  represent  the 
simplest  form  of  sexual  reproduction  in  this  division.  The 
species  are  all  small  green  fresh-water  plants,  composed  of 
dichotomously  branching  filaments,  which  are  arranged  ra- 
di;illy  upon  a  central  disc  (or  sometimes  arranged  upon  irreg- 
ularly branched  threads)  ;  the  diameter  of  each  cushion- 
like  ma^s  is  from  1  to  2  mm.  (.04  to  .08  in.). 

361. — Reproduction  takes  place  both  sexually  and  asexu- 
;illy.  The  latter  is  by  means  of  zoospores  whicli  arise  in  the 
vegetative  cells,  by  the  protoplasmic  contents  becoming,  in 
each  case,  converted  into  a  single  spherical  bi-ciliated  zoo- 
spore,  which  escapes  through  a  round  hole  in  the  cell-wall 
(D,  Fig.  183). 

362. — The  sexual  organs  and  process  bear  some  resem- 
blance to  those  of  CEdogoninceae.  The  female  organ,  the 


272  BOTANY. 

carpogonium,  is  a  single  cell,  wide  below,  and  tapering  above 
into  a  long  slender  canal,  the  trichogyne,  which  is  open  at 
its  apex  (A,  og,  Fig.  183).  The  carpogonium  is  the  terminal 
cell  of  a  branch,  which  in  its  development  swells  up,  while 
at  the  same  time  elongating  into  a  tube.  In  the  swollen  basal 
portion  there  is  a  considerable  mass  of  protoplasm,  which  is 
the  essential  part  to  be  fertilized. 

The  male  organs,  the  antheridia,  are  formed  as  flask-shaped 
protuberances  which  grow  out  of  adjoining  cells  ;  they  be- 


Pig.  IBS.—Ooleochcete  ptUvinata.  A,  portion  of  fertile  plant ;  an,  antheridia ;  wj, 
carpogonia— each  with  a  trichogyne  ;  z.  z,  epennatozoids ;  h,  hairs,  with  Bheathinq 
bases.  A.  fertilized  carposoniiim  surrounded  by  covering,  r  f"  pericarp''),  the  whole 
constituting:  the  sporocnrp.  6',  sporocarps  burst  open,  showing  the  interior  tissue, 
sch ;  r.  cortical  cover  (•'  pericarp  ).  D,  zoospore*  (swarm-spores)  from  C.  X  350.— 
After  Priugsheim. 

come  cut  off  from  the  cells  from  which  they  grow,  by  trans- 
verse partitions.  In  each  antheridium  a  single  oval  bi- 
ciliate  spermatozoid  is  formed  (A,  z,  z,  Fig.  183). 

363. — Fertilization  is  doubtless  effected  by  these  sperma- 
tozoids  coming  in  contact  with  the  protoplasm  of  the  carpo- 
gonium, but  the  actual  entrance  of  the  former  has  not  yet 
been  seen.  After  fertilization  the  protoplasmic  mass  in  the 
carpogonium  increases  considerably  in  size,  and  becomes 
surrounded  by  a  cellulose  coat  of  its  own.  The  cells  which 


FLORIDE^!.  273 

support  the  carpogonium  send  out  lateral  branches,  which 
grow  up  and  closely  invest  it,  and  by  their  growth  finally 
cover  it  entirely  (excepting  the  trichogyne)  with  a  cellular 
"pericarp"  (B,  r,  Fig.  183).  The  whole  mass,  including 
the  fertilized  carpogonium  and  its  investing  ''pericarp," 
constitutes  the  simplest  form  of  sporocarp. 

364.  —  The  germination  of  the  sporocarp  takes  place  (the 
next  spring)  by  the  swelling  of  the  protoplasmic  contents, 
and  the  consequent  rupture  of  the  "pericarp;"  the  inner 
portion  becomes  changed  into  a  many-celled  mass  (C,  Fig. 
183),  which  gives  rise  to  bi-ciliate  zoospores  closely  resembling 
those  developed  from  the  vegetative  cells.  From,  each  zoo- 
spore  a  new  plant  eventually  arises. 

(a)  These  little  plants  occur  in  fresh-water  pools  as  little  green 
masses  adhering  to  leaves,  sticks,  etc.  According  to  Wood,  we  have 
probably  two  species. 

(6)  The  sexual  process  and  the  development  of  the  sexual  organs  oc- 
cur in  May,  June,  and  July. 

(e)  Nothing  can  be  attempted  in  this  place  to  determine  the  grouping 
of  Ooleochcete  with  other  Carposporese.  Its  evident  relationship  to  the 
Perisporiaceae  in  the  Ascomycetes  suggests  that  possibly  the  latter 
class  may  have  to  be  broken  up,  and  the  first  two  orders  united  with 
C'lleochate  to  form  a  new  class.  Certainly  the  relationship  between 
Coleochcete,  Perisporiacese,  and  Tuberacese  is  much  closer  than  between 
the  two  last  named  and  the  other  orders  of  Ascomycetes.  There 
can  be  but  little  doubt  that  the  Ascomycetes  are  held  together  by  char- 
acters which  are  now  of  but  secondary  value,  drawn  as  they  are  from 
the  asexual  fruiting,  while  characters  which  are  of  far  greater  value, 
derived  from  the  sexual  organs,  are  disregarded. 


§  II.   CLASS 

365.  —  In  the  Florideae  the  reproduction  is  generally 
asexual  as  well  as  sexual.  The  former  is  by  means  of  cells 
which  originate  from  a  division  of  a  mother-cell  into  four 
parts  ;  on  account  of  their  number  they  have  received  the 
name  of  tetraspores  (A,  B,  t,  t,  Fig.  184).  These  appear 
to  replace  the  swarm-spores  of  other  algae,  and  may  also  be 
compared  to  the  conidia  of  certain  fungi  ;  they  are  destitute 
of  cilia,  and  are,  as  a  consequence,  not  locomotive.  They 
develop  from  the  terminal  cells  of  lateral  branches,  or  from 
the  cells  of  ordinary  thick  tissues,  sometimes  deeply  imbedded. 


274 


BOTANY. 


366.  —  The  sexual  organs  consist,  as  in  Coleochcete,  of 
carpogonia  and  antheridia.  The  latter  are  composed  of  one 
or  more  mother-cells,  situated  singly  or  in  groups  on  the 
ends  of  branches  (A  and  B,  a,  a,  Fig.  185).  The  sperma- 
tozoids  are  small,  round  bodies,  which  are  destitute  of  cilia, 
and,  as  a  consequence,  incapable  of  independent  movement 
(A,  x,  Fig.  185)  ;  they  are  carried  about  by  currents  of 
^  water,  and  in  this  way  brought  to 

the  carpogonia. 

367.  —  The  carpogonia  are  some- 
what variable  as  to  their  complex- 
ity, being  much  more  simple  in 
the  lower  orders  than  in  the  high- 
er. In  the  genus  Nemalion  the  car- 
pogonium  consists  of  a  single  cell 
(B,  I,  Fig.  185),  resembling  Coleo- 
chcete closely  in  this  respect.  It 
is  thickened  below,  and  elongated 
above  into  the  trichogyne,  which 
differs  from  that  in  Coleochcete  in 

iiot  to^  °pen  at  the  top-  When 

the  sPei'matozoids  are  set  free  from 
the   anthendia  they  attach  them- 

,  ,  ,        ,    .    ,  , 

selves  to  the  trichogyne,  as  shown 
in  Fig.  185  ;  the  result  of  this  contact  of  the  spermatozoids 
with  the  trichogyne  is  the  fertilization  of  the  carpogonium, 
which  immediately  enlarges,  and  at  the  same  time  undergoes 
division  into  many  cells,  which  grow  into  short,  crowded 
branches,  bearing  a  spore  at  the  end  of  each  (D  and  E, 
Fig.  185).  To  this  growth,  which  includes  the  spores  and 
the  short  branches  which  bear  them,  and  which  resulted  from 
the  fertilization  of  the  carpogonium,  the  name  of  sporocarp  is 
applied.  In  the  genus  under  consideration  the  sporocarp  is 
a  comparatively  simple  growth,  as  compared  with  the  degree 
of  complexity  it  reaches  in  some  other  orders  of  this  class. 

368.  —  In  the  genus  Lejolisia,  the  carpogonium,  before 
fertilization,  consists  of  several  cells  (A,  b,  Fig.  185)  ;  the 
trichogyne  is  in  connection  with  certain  of  the  exterior  cells 
of  the  carpogonium,  but  not  directly  with  its  central  cell. 


in  a  cup-phaped  extremity  of  a 

brauch.  —  After  Berkeley. 


FLOR1DEM 


275 


Upon  fertilization  taking  place,  which  is  as  in  Nemalion, 
the  peripheral  cells  of  the  carpogonium  (excepting  those  con- 
stituting the  trichophore — i.e.,  the  trichogyne-bearer)  undergo 
division,  and  become  developed  into  articulated  branches, 
which  lie  side  by  side,  and  form  a  more  or  less  spherical 


Fig.  185.—^!,  Lejolisia  mediterranea.    r,  root-like  processes  (rhizoids) ;  a,  antherid- 
inm  ;  x,  spermato/oids  ;  f>,  carpi igonium,  with  tricfiogyne.tn  the  apex  of  which  two 


spennat  .zbids  ar.-  attached ;  s,  sec 

Nemalion  muUifidmii.    a,   branch  with  antlieriaia  ana  sperm! 

nium,  with  tricliogyne,  the  latter  with  spermatozoids  attached  to  its  apex.    D  and  E, 

development  of  the  sporocarp  of  Nemalion.     x  150.— After  Bornet. 


of  ripe  sporocarp  ;  (,  ripe  spore  escaping.     Ji, 
a,   braii':h  with  antheridia  and  spennatozoids  ;  b,  carpogo 


organ,  the  so-called  "pericarp."  In  the  meantime  the  cen- 
tral cell' of  the  carpogonium  develops  processes  or  outgrowths 
which  eventually  become  spores,  occupying  the  cavity  of  the 
"pericarp"  (A,  s,  Fig.  185).  An  interesting  fact  in  this 
connection  is  that  neither  the  trichogyne  nor  trichophore 
take  part  in  the  development  subsequent  to  fertilization  ;  in 
other  words,  the  cells  which  directly  receive  the  influence  of 
the  spermatozoids  do  not  themselves  undergo  a  subsequent 
development,  but  adjoining  ones  do  develop,  on  the  one 
hand,  into  the  spores,  and  on  the  other  into  the  filaments 
of  the  pericarp.  The  sporocarp  in  this  genus  is  thus  seen 
to  be  somewhat  more  complex  than  in  Nemalion,  including 


KOTANY. 


the  pericarp,  iu  addition  to  the  parts  found  in  the  latter 
genus. 

369.  —  In  the  genus  Dudresnaya  there  is  a  curious  and 
complicated  sexual  process.  After  the  fertilization  of  the 
trichogyne,  a  long  "  connecting  tube"  (ct,  Fig.  186)  grows  out 
from  beneath  the  trichophore,  and  comes  in  contact  with  the 

fertile  brandies  (/,  /, 
Fig.  186),  to  the  ter- 
minal cells  of  which  it 
becomes  closely  applied. 
These  fertile  branches, 
which  grow  as  lateral 
branches  on  the  same 
plant  as  the  trichogyne, 
are  the  true  female  or- 
gans, and  fertilization 
is  consummated  only 
,,  when  the  connecting 
tube  comes  in  contact 
and  coalesces  with 
them.  The  result  of 
this  curious  process  is 
the  production  of  a  spo- 
rocarp  on  each  fertile 

Fig.  186.—  Dudrennaya  pvrpitrifera.  tr,  tricho- 
gyne,  with  spermatozoids  attached  ;r/,connectin<;- 
tube  which  grows  out  from  below  the  base  of  the 
trichogyne.  and  comes  in  contact  with  the  fertile 
branches,  /,/;  ct',  young  connecting-tube.—  After  and  interesting  one,  but  un- 

fortunately   it    cannot     be 

studied  readily  except  near  the  seaside,  and  even  then,  from  tlie 
fact  that  the  species  mostly  inhabit  the  deeper  waters,  it  presents  many 
difficulties.  The  plants  are  mostly  red  or  violet  in  color,  although  this 
is  not  due  to  the  absence  of  chlorophyll.  The  red  color  is  due  to  the 
presence  of  a  pigment  (phycoerythTine),  which  is  soluble  in  cold  fresh 
water  ;  its  solution  is  carmine-red  in  transmitted  light  and  reddish  yel- 
low in  reflected  light.  Upon  extraction  of  the  phycoerythrine  the 
plants  are  found  to  be  green  from  the  presence  of  the  chlorophyll 
which  had  been  masked  by  the  brighter  pigment. 

(6)  There  are  many  orders  in  this  class,  the  following  of  which  are 
represented  in  the  United  States.* 

*  The  sequence  of  the  orders  is  that  given  by  Dr.  Farlow  in  his 
"  List  of  the  Marine  Algae  of  the  United  States,"  1876,  published  in  the 


/_\  fi,;Q  ,,IORH  ;H  n  im-o-d 
W    1  lus  class  ls  a  Jarge 


FLORTDEJ2.  277 

Order  Rhodomeleae,  of  which  Daaya  and  Polysiphonia  are  common 
genera. 

Order  Chylodadiem,  represented  by  only  two  Californian  species. 

Order  Sphwrococcoidece,  represented  abundantly  by  species  Delesserid. 

Order  Coralliiiece,  containing  plants  which  are  remarkable  for  the 
large  amount  of  calcium  carbonate  they  contain.  Cor<illina  is  abundant 

Order  Gelidiece,  represented  by  Gelidium. 

Order  Ifypnete,  including  only  a  few  species  of  one  genus  Hypnea. 

Order  Rhodymeniem,  of  which  Rhodymenia  and  Lomentaria  are  com 
mon  genera.  Rhodymenia  palmata,  the  "  Dulse  "  of  our  coasts,  is  used 
as  human  food. 

Order  Spongiocarp  ce,  with  one  species  of  Polyides. 

Order  Squamariem,  with  one  species  of  Peyssonnelia. 

Order  Batrachospermece,  to  which  Nemalion  (Fig.  185,  B)  belongs. 

Order  Wrangeliece,  with  two  species  of  Wrangelia. 

Order  Gigartinem,  of  which  Chondrus  crispus,  the  Irish  moss  so 
largely  used  for  food,  for  making  blanc  mange,  etc.,  is  the  best-known 
of  the  many  species  on  our  coasts. 

Order  Cryptonemieee,  represented  mainly  on  our  Southern  and  Pacific 
coasts.  Schizynemia  edulis,  of  Europe  and  our  Western  coasts,  is 
used  as  human  food. 

Order  Dumon  iece,  to  which  Halosaccion  of  our  Eastern  coast  belongs. 

Order  Spyridiem,  represented  by  Spyridia  of  our  Eastern  coast. 

Order  Ceramiece.  This  order  contains  algae  "  which  are  either  strictly 
monosiphonous  (i.e.,  composed  of  a  single  tube)  and  filiform,  or  which 
are  more  simple  in  their  structure  than  others,  approaching  in  this  re- 
spect the  Confervaceae.  It  abounds  in  species  which  display  the  most 
exquisite  combination  of  ramification  and  coloring."  A  large  portion 
of  our  marine  flora  is  composed  of  individuals  of  this  order,  as  "  they 
abound  on  our  coasts  in  every  little  rocky  pool,  onevery  piece  of  wood- 
work exposed  to  the  waves,  on  rocks  and  stones,  and,  above  all,  on  the 
stems  of  the  larger  or  firmer  algae,  or  even  on  marine  Phanerogams, 
which  they  fringe  in  the  most  exquisite  way  with  every  shade  of  red, 
from  a  bright  rose  to  purple."f 

Lejolisia  (A,  Fig.  185)  and  Dudresnaya  (Fig.  186)  are  genera  of  this 
order.  CallitJiamnion  is  represented  by  many  species  on  both  our  At- 

R 'port  of  the  V.  8.  Fish  Commissioner  for  1875.  It  is  modified  from 
Tluuet's  arrangement.  The  arrangement  of  the  orders  and  the  group- 
ing of  genera  into  orders  are  not  based  upon  sexna1  characters,  and  con- 
sequently must  be  regarded  as  to  a  considerable  extent  artificial.  The 
first-named  orders  in  the  list  are  higher  than  those  that  follow. 

f  "  Introduction  to  Cryptogamic  Botany,"  by  M.  J.  Berkeley,  1857,  p. 
178.  The  student  is  also  referred  to  Harvey's  "  Nereis  Boreali-Ameri- 
c.ina,"  a  "  Contribution  to  a  History  of  the  Marine  Algae  of  North 
America,"  published  by  the  Smithsonian  Institution,  1852  to  1858. 


278  SOTANT. 

lantic  and  Pacific  coasts.     Ceramium  rubrum  is  a  very  common  spe- 
cies. 

(c)  The  order  Corallinrse  was  represented  in  the  Silurian  by  a  spe- 
cies of  Cvrallina.  Others  occur  iu  the  Secondary  (Jurassic)  and  Ter- 
tiary. Chondrites  represented  the  order  Gigartinese  from  the  Permian 
to  the  Tertiary  (Miocene).  The  order  Sphaerococcoidese  was  represented 
in  the  Secondary  by  Jurassic  species  of  Sphcerococcites,  and  in  the  Ter- 
tiary by  Delesseria.  In  the  order  Rhodoineleae  a  species  of  Polysi- 
phonides  occurs  as  a  fossil  in  the  Tertiary. 

§  III.  CLASS  ASCOMYCETES. 

370. — This  large  class  includes  chlorophyll-less  plants 
which  differ  much  in  size  and  appearance,  but  which  agree 
with  one  another,  and  differ  from  all  other  Carposporeae  in 
producing  their  spores  (ascospores)  in  sacs  (asci}.  The  sex- 
ual reproductive  organs,  consisting  of  carpogonia  and  anthe- 
ridia,  are  produced  upon  the  mycelium,  and,  after  fertiliza- 
tion, a  sporocarp,  which  includes  the  asci  and  ascospores,  is 
developed.  The  asci  are,  at  first,  single  cells  at  the  ends  of 
branches  which  result  from  fertilization  of  the  carpogonium  ; 
in  these,  ascospores  arise  by  internal  cell-formation.  The 
most  common  number  of  ascospores  is  eight  in  each  ascus, 
but  it  sometimes  exceeds,  and  frequently  falls  short,  of  this 
number,  there  being  often  no  more  than  one  or  two.  The 
asci  are  in  many  cases  arranged  side  by  side  in  a  compact 
mass,  forming  a  spore-bearing  surface,  the  liymenium.  In 
addition  to  the  ascospores  there  are  generally  one  or  several 
other  kinds  of  spores,  which  are  developed  on  the  same  my- 
celium as  the  sexual  organs,  or  on  another,  the  latter  case 
being  one  of  an  alternation  of  generations. 

371. — The  Ascomycetes  are  readily  separated  into  a  num- 
ber of  well-marked  groups,  which  may  not  all  turn  out  to  be 
coordinates.  For  the  present  they  may  be  treated  as  orders. 

372.— Order  Perisporiacese  (or  Erysiphacese).  In  this 
order  the  plants,  which  are  mainly  parasitic,  are  composed 
of  branching  articulated  filaments,  which  form  a  white  web- 
like  film  upon  the  surface  of  the  leaves  and  stems  of  their 
hosts.  There  are  both  sexual  and  asexual  spores,  and  of 
the  latter  there  are  in  most  cases  two  or  three  different  kinds, 
which  are  produced  earlier  than  those  that  result  from  a  for- 


PERI8PORIACEJE. 


tilization.  The  sexual  organs  and  the  sporocarp  resulting 
from  the  act  of  fertilization  bear  a  striking  resemblance  to 
those  of  Coleochcete,  the  difference  being  such  as  may  be  ac- 
counted for  by  considering  the  aquatic  habits  of  the  one,  and 
the  aerial  and  parasitic  or  saprophytic  habits  of  the  other. 

373. — In  the  parasitic  Perisporiacecethe  jointed  filaments 
of  the  mycelium  closely  invest  and  cover  the  leaves  and 
other  tender  parts  of  their  hosts,  and  draw  nourishment 
from  them  by  means  of  haustoria,  which  project  as  irregular 
pullulations  from  the  side  of  ^ 

the  hyphae  next  to  the  epider- 
mis (Fig.  187)  ;  these  haustoria 
apply  themselves  closely  to  the 
epidermis  cells,  and,  in  some 
cases  at  least,  appear  to  penetrate 
them.*  The  crossing  and  rami- 
fying hyphae  soon  send  up  many 
vertical  branches,  in  which  parti- 
tions form  at  regular  intervals; 
the  cells  thus  formed  are  at  first 
oblong  and  cylindrical,  with  flat- 
tened ends  ;  but  the  topmost  one 
soon  becomes  rounded  at  its  ex- 
tremities, and  the  others  follow  ng_  18r._^^  (Oidium) 
in  quick  succession,  thus  giving  h™^,*pp^ 

rise  to  a  niOlllllform  rOW  of   loose-    epidermis  of  the  leaf  of  the  vine,  and 
,       i      i      IT     ,  •      i  i     i     to  which  it  is  fastened  by  the  haus- 

ly  attached  elliptical  or  rounded  toria.  A/  &,  an  isolated 'piece  of  a 


cells,  the  conidia  (T,  Fig.   188). 

These  fall  off  and  germinate  at  AfterVonMohl- 

once  by  pushing  out  a  germinating  tube,   which  gives  rise 

to  a  new  mycelium. 

374. — The  sexual  process,  which  in  most  species  takes 

*  De  Bary  (•'  Morphologic  und  Physiologic  der  Pilze,"  etc.,  1865,  p. 
19)  says  that  the  haustoria  of  the  investigated  species  do  not  penetrate 
into  the  epidermis  cells  ;  while  Sachs  ("  Lehrbuch,  4te  Auflage,"  1874, 
p.  312)  says  that  haustoria  are  sent  into  the  epidermis  cells.  A  myce- 
lium on  Poa  pratensis  (probably  of  Erysiphe  communis)  examined  in 
1877  appeared  to  have  sent  its  haustoria  through  the  outer  walls  of 
tho  epidermis  cella 


280 


BOTANY. 


place  late  in  the  season,  is  as  follows  :  where  two  filaments' 
cross  each  other  or  come  into  close  contact  they  swell 
slightly  and  send  out  from  each  a  short  branch  ;  one  of  these 
thickens  and  assumes  an  oval  form,  becoming  at  the  same 
time  separated  from  the  filament  by  a  partition  ;  this  is  the 
carpogonium  (///,  c,  Fig.  188,  and  c,  Fig.  189).  From  the 
swollen  part  of  the  other  filament  a  corresponding  branch  is 
given  off,  which  grows  up  in  contact  with  the  carpogonium  ; 
near  its  extremity  it  forms  a  partition,  which  thus  cuts 


Fig.  188.— 7. ,  conidia-bearing  hypha  of  Sphcewtheca  pannona.  IT.,  the  ripe  pporo- 
carp  of  the  same  ;  a,  the  single  ascup  escaping  from  the  perithecium.  h;  only  a  few 
of  the  hypha-like  appendages  of  the  perithecium  are  shown.  777,  sexual  organs  of  tho 
same;  c,  carpogonium  :  p.  antlteridmm.  IV..  the  formation  of  the  perithecinm  by 
the  growth  of  the  enveloping  cells,  A  ,•  c,  carpogonium  ;  p.  antheridium.  V.,  section 
of  the  voting  sporocarp  of  Sphmrotfieca  Castagnei ;  c,  oirpogonium  :  a.  the  young 
aecus ;  A,  A,  cells  of  the  perithecium.  7.  and  II.  after  Tulasne  ;  777.-  V.  after  De 
Bary. 

off  a  small  rounded  terminal  cell,  the  antheridium  (///.,  p, 
Fig.  188,  and  b,  Fig.  189).  Immediately  after  the  forma- 
tion of  the  antheridium  the  effect  of  fertilization  shows  itself 
in  the  growth  from  below  the  base  of  the  carpogonium  of  eight 
or  ten  branches,  which  join  themselves  to  its  sides  and  to  one 
another,  finally  completely  investing  it  (IV.,  Fig.  188,  and  d, 
Fig.  189).  Each  of  these  joined  enveloping  branches  be- 
comes transversely  divided  several  times,  thus  giving  to  the 
covering  layer  a  distinctly  cellular  structure.  The  enclosed 


PERISPORIACE^E.  281 

carpogonium  becomes  divided  in  such  a  way  that  from  one 
portion  of  it  an  inner  layer  of  cells  is  formed  in  contact  with 
the  outer  envelope  described  above.  From  the  remaining 
central  part  of  the  carpogonium  one  ascus  (in  Sphcerotheca 
and  Podosphcera),  and  in  the  other  genera  two  or  more,  are 
developed.  In  each 
ascus  from  two  to  & 

eight  ascospores  arise 
by  internal  cell-for- 
mation (II,  a,  Fig. 
188).  The  sporocarp 
(technically  called 
the  perithecium)  be- 

COmeS  dark  and  hard      acearum.    a,  threads  01  mycelium  ;  6,  anthcridium; 
c,  carpogonium  ;  d,  youm'  sporocarp  ;  e,  older  sporo- 
and     from      Its     Ollter    carp.    Highly  magnified.-After  OSrsted. 

cells  there  grow  out  long  filaments  (technically  known  as 
appendages),  which  are  usually  septate,  and  of  a  particular 
shape  in  each  genus  ;  thus  in  Podosphcera  and  Microsphcera 
they  are  dichotomously  branched  ;  in  Phyllactinia  they  are 
straight  and  needle-shaped  ;  in  Uncinula  they  are  curved 
regularly  at  their  tips  (Fig.  190),  while  in  the  other  genera 
they  are  tortuous,  and  simple  or  irregu- 
larly branched.  The  perithecia  remain 
during  the  winter  upon  the  fallen  and 
decaying  leaves,  and  finally,  by  rupturing, 
permit  their  asci,  with  their  contained 
ascospores,  to  escape. 

375, — There  are  usually  present  some 
hcim$a  *ddun-  °^ner  organs,  which  bear  small  spore-like 
i  /'  the  appendages  of  bodies,  but  whose  function  is  not  certain- 

the      perithecium      are 

curved  in  a  circinate  ly  known.       These    organs,    which    are 

manner  at  their  free  ex-      J  t 

tremities.— After  cooke.  known  as  pyciiidia,  are  clavate,  ovate,  or 
nearly  spherical  in  shape ;  the  bodies  they  contain  (the  so- 
called  pycnidio-spores)  in  their  cavities  are  usually  oblong 
or  elliptical. 

376. — In  the  genus  Eurotium  (composed  of  saprophytes) 
the  conidia  are  produced  in  a  slightly  different  way.  The 
mycelium,  which  is  common  on  articles  of  food,  as  bread, 
pastry,  preserved  fruit,  etc.,  and  on  poorly  dried  specimens  iu 


282 


BOTANY. 


the  herbarium,  sends  up  vertical  hyphse,  which  swell  up  at 
th#  top,  and  bear  a  large  number  of  small  protuberances  or 
branches,  the  sterigmata  (A,  c,  st,  Fig.  191).  Each  sterigma 
produces  gradually  a  long  chain  of  conidia,  so  that  each 


Pig.  191.  —  Evrotium  repens.  A,&  portion  of  the  mycelium,  with  erect  hypl 
hearing  at  its  top  a  radiating  cluster  of  Bterlgmata,  st,  from  which  the  conjoin 
fallen  ;  as,  yourg  cm  -polonium—  below  it  a  younger  branch  is  beginning  to  coil 


low  it  a  younger  branch  is  beginning 
/;,  the  carpogonium,  ax,  and  the  anth 


hypli.-i.  r, 
njoin  hiive 


spi- 

rally to  form  another  carpogonium.  /;,  the  carpogonium,  ax,  and  the  antheridiuni,  p. 
C,  the  same  banning  t<>  be  •nrrounded  by  the  enveloping  branches  wlrch  grow  out 
from  its  base.  D,  gporocarp.  K,  F,  sections  of  unripe  sporoearps  ;  jo.  outer  wall  : 
f.  inner  cells  of  sterile  tissue  ;  a*,  developing  ciirpogoniiim,  giving  rise  to  branches 
Irom  which  asci  are  produced.  G,  an  ascus  containing  eight  ascospores.  //,  ripe  as- 
cospore.  Highly  magnified.  —  After  De  Bary. 


vertical  hypha  is  terminated  by  a  round  mass,  made  up  of 
these  radiating  strings  of  conidia.  The  sexual  organs  appear 
a  little  later  than  the  conidia.  The  end  of  a  branch  of  the 
mycelium  becomes  coiled  into  a  hollow  spiral  (A,  as,  Fig. 


191),  which  constitutes  the  carpogonium,  and  which  is  soon 
divided  by  cross-partitions  into  several  cells.  From  below 
the  spiral  there  pushes  out  a  branch  (the  antheridium),  which 
grows  upward,  and  brings  its  apex  in  contact  with  the  upper 
cells  of  the  carpogonium  (B,  Fig.  191).  After  this  pro- 
cess, which  constitutes  fertilization,  other  branches  grow  up 
around  the  carpogouium,  and  finally  completely  enclose  it, 
as  in  the  parasitic  genera  described  above  (C,  D,  E,  and  F, 
Fig.  191).  By  the  subsequent  growth  and  division  of  the 
enveloping  branches,  the  carpogonium  becomes  imbedded  in 
a  thick  parenchymatous  mass.  In  the  meantime,  from  the 
cells  of  the  carpogonium  branches  bud  out  and  penetrate  the 
surrounding  parenchyma  (F,  Fig.  191),  and  finally  produce 
eight-spored  asci  on  their  extremities  (G,  Fig.  191)  ;  after  a 
time  the  asci  are  dissolved,  and  the  sporocarp,  now  of  a  sul- 
phur-yellow color,  contains  only  loose  ascospores,  intermingled 
with  the  debris  of  the  broken-up  asci  and  parenchyma.* 

The  plants  of  this  order  are  abundant  and  easily  studied.  The 
following  partial  list  will  enable  the  student  to  intelligently  begin  his 
investigations : 

PARASITIC  PLANTS. 

A.  Peritheciura  containing  a  single  ascus. 

Appendages  floccose Genus,  Sphcerotheca. 

Appendages  dichotomous "        Podospfwera. 

B.  Perithecium  containing  many  asci. 

Appendages  needle-shaped,  rigid Genus,  Phyllactinid. 

Appendages  hooked "       Uncinula. 

Appendages  dichotomous "       Microsphara. 

Appendages  floccose "       Erysi/phe. 

Spharotheca  pannosa  occurs  on  wild  gooseberries,  on  whose  stems, 
leaves,  and  fruits  it  forms  brown  felted  masses.  In  its  conidial  stage 
it  is  frequently  so  abundant  on  the  leaves  of  roses  as  to  entirely  destroy 
them. 

8.  Castagnei  sometimes  occurs  upon  the  hop  in  such  abundance  as  to 
destroy  the  crop. 

*  The  student  is  referred  to  Do  Bary's  "  Morphologic  und  Physiolo- 
gic der  Pilze,"  etc.,  18(55,  p.  162.  A  translation  of  the  part  relating  to 
the  Krysiphei  appeared  iu  "  Grevillea,"  Vol.  I.,  p.  152. 


284  BOTANY. 

Podospheera  Kunzei  may  be  fouud  on  tlie  leaves  of  the  cherry  and 
apple,  which  it  injures  greatly  in  some  cases  ;  the  couidia  may  be  ob 
served  in  midsummer,  and  the  sexual  process  and  formation  of  perithecia 
in  autumn. 

Phyllactinia  guttata  may  be  obtained  in  great  abundance  in  autumn 
upon  the  leaves  of  the  hazel  and  ironwood. 

Uncinula  adunca  is  frequently  abundant  on  willow  leaves  in  the 
autumn  (Fig.  190). 

U.  spirulis  is  the  species  to  whose  conidial  stage  the  name  Oidiii)i> 
Tuckeri  has  hitherto  been  applied  in  this  country.  It  occurs  on  the 
grape,  and  does  great  injury.  According  to  Dr.  Farlow,  it  is  not  cer- 
tain that  the  so-called  Oidium  Tuckeri  of  this  country  is  identical  with 
what  is  so  named  in  Europe,  and  which  is  even  more  injurious  to 
grapes  in  that  country  than  in  this. 

U.  circinata  occurs  on  the  leaves  of  the  red  and  silver  maples  in  the 
autumn. 

MierospJiara  Friesii  is  one  of  the  most  common  species.  It  may  be 
found  in  the  conidial  stage  at  any  time  during  the  summer  on  the 
leaves  of  the  lilac,  and  late  in  summer  or  in  autumn  the  perithecia  are 
usually  abundant. 

M.  txtensa  is  a  nearly  related  species,  often  very  common  on  oak 
leaves. 

Erysiphe  lamprocarpa,  \vhich  may  be  found  on  Composite  (especially 
on  Helianthus),  and  also  on  wild  verbenas,  is  readily  distinguished  by 
its  two-spored  asci.  The  commonness  of  this  species  makes  it  a  valua- 
ble one  for  study. 

E.  tortUis  may  be  frequently  obtained  on  the  leaves  of  the  Virgin's 
Bower. 

E.  Ma/rtii  occurs  in  great  abundance  upon  cultivated  peas,  greatly 
to  their  injury.  In  summer  it  covers  the  leaves  and  fruits  with  a 
white  mould-like  growth,  which  is  the  conidial  stage  of  the  parasite  ; 
as  autumn  approaches  the  mycelium  becomes  darker,  and  finally  large 
numbers  of  perithecia  may  be  found. 

E.  communis  appears  in  early  summer  on  grass  leaves,  where  the 
vegetation  is  rank.  In  autumn  the  perithecia  may  be  found  in  abun- 
dance on  Uammculaceae  (especially  on  Anemone)  growing  in  grass. 


SAPROPHYTIC  PLANTS. 

Eurotiwn  Tierbariorum  may  be  readily  obtained  for  study  by  placing 
a  few  green  specimens  of  Phanerogams  in  an  ordinary  plant-press  and 
permitting  them  to  remain  until  they  become  mouldy.  The  conidial 
stage,  which  first  appears,  is  what  has  long  been  described  as  a  distinct 
fungus  under  the  name  of  A&pergittm  glancii*  ;  somewhat  later  the 
bright  yellow  perithecia  will  be  found  in  abundance, 


TU3ERAGEJ&. 


285 


377. — Order  Tuberaceae.  In  this  order  the  sporocarp  is 
a  rounded  underground  mass,  composed  of  pseudo-paren- 
chyma and  the  asci  with  their  contained 
ascospores.  In  the  Truffle  (Tuber)  the 
sporocarp  is  large,  and  dark  colored  and 
warty  on  the  exterior.  Internally  it  con- 
tains narrow  tortuous  chambers,  on  whose 
walls  are  the  asci,  containing  two  to  eight 
usually  areolate  or  echinulate  ascospores 
(Fig.  192,  A  and  B).  The  sexual  organs, 
as  well  as  the  early  stages  of  the  Truffles, 
are  unknown. 

378. — The  common  blue  mould,  found 
on  all  sorts  of  decaying  bodies,  and  known 
as  Penicillium  glaucum  (or  P.  crusta- 
ceum),  has  recently  been  found  by  Brefeld 
to  be  a  member  of  this  order.  Its  life-his- 
tory is  now  pretty  well  known,  and  it  in- 
dicates what  the  early 
stage  of  the  Truffle 
must  in  all  probability 
turn  out  to  be.  In 
Penicillium  the  my- 
celium sends  up  a  large 
number  of  vertical 
hyphse,  which  branch 
at  the  top,  and  produce  chains  of  conidia 
(Fig.  193).  It  appears,  from  Brefeld's 
researches,  that  this  stage  is  the  only 
one  which  the  plant  passes  through 
under  ordinary  circumstances  ;  by  care- 
ful culture,  however,  he  succeeded  in 
making  it  pass  into  its  sexual  stage. 
I  le  found  tha  sexual  organs  to  be  in  all 
essentials  similar  to  those  of  Eurotium 
(Fig.  191) ;  like  it,  the  carpogonium  is  a  spirally  twisted  end 
of  a  hypha,  and  the  antheridium  a  branch  growing  out  from 
below  it.  The  subsequent  development  is  also  much  as  in 
Kuratium;  a  thick  covering  forms  over  the  fertilized  carp- 


Fig.  192.— Tuber  me- 
Idnosporum.  A,  a  por- 
tion of  a  transverse  sec- 
tion, showing  the  asci, 
with  contained  asco- 
spores ;  JB,  an  ascus 
with  ripe  ascospores. 
Both  much  magnified. — 
After  Tulasne. 


193.  —  Penirillium 
c/iartarti/ii,  showing  co- 
nidia-bearing  hypha  ;  at 
the  side  is  pnowu  an  iso- 
lated chain  of  couidiu. 
Magnifted.-AfterCooke. 


286 


BOTANY. 


ogonium  by  the  growth  of  many  basal  enveloping  branches, 
and  inside  of  this  the  carpogonium  increases  in  size,  and 
sends  out  branches,  which  finally  produce  eight-spored  asci. 
The  little  tuber-Kke  mass  thus  formed  is  yellowish,  and  of 
the  size  and  appearance  of  a  coarse  sand  grain. 

(a)  Aside  from  Penicillium,  we  have  in  this  country  very  few  repre- 
sentatives of  this  order.     Two  or  three  species  of  Tuber  have  been 
recorded,  and   two  of  Elaphomy- 
ces* 

(b)  In  Europe,  where  they  grow 
abundantly,  Tuber  wstivum,  T. 
melanosporum,  and  T.  magnatum 
are  gathered  for  food.  They  are 
found  by  the  aid  of  dogs  and  pigs, 
which  are  trained  to  search  for 
them. 

379. — Order  Helvellaceee 
(or  Discomycetes).  These 
are  for  the  most  part  disc-like 
or  cup -like  saprophytes, 
which  frequently  attain  large 
dimensions.  The  hymenium 
is  spread  over  the  upper  and 
generally  exposed  surface  of 
the  full-grown  plant,  which 
is  in  reality  the  sporocarp. 

In  Peziza,  one  of  the  prin- 
cipal genera,  the  sexual  or- 
gans occur  on  the  mycelium 
on  or  in  the  ground ;  the 

ceptacle  is  developed.—  After  Tulasne.          ends    of   Certain    liyplise    SWell 

up  into  ovoid  vesicles,  the  carpogonia  (Figs.  194  and  195), 
each  of  which  is  provided  with  a  more  or  less  bent  and 
curved  appendage,  the  tricliogyne  (Fig.  195,  and/,/,  Fig. 
194).  From  below  the  carpogonium  a  branch  grows  out, 
and,  curving  around,  becomes  closely  applied  by  its  tip  to 
the  extremity  of  the  trichogyne  (Figs.  194  and  195).  The 

*  See  Bulletin  of  the  Torrey  Botanical  Club,  November,  1878,  for  the 
ppecies  of  Tuber  discovered  in  North  America. 


HEL  VELLAOBJS. 


287 


immediate  result  of  this  process  of  fertilization  is  the  bud- 
ding out  and  upward  growth  of  a  large  number  of  hyphas  from 
beneath  the  carpogonium 
(B,  Fig.  194) ;  these  form 
a  dense  felted  mass,  from 
Avhich,  eventually,  there 
rise  vertical,  closely 
crowded  hyphae,  which 
form  the  hymenium  (A, 
h,  Fig.  19G).  In  the  ter- 
minal portions  of  certain 
of  the  vertical  hyphse 
the  protoplasm  condenses 
around  certain  points,  and 
thus  gives  rise  to  asco- 
spores  (B,  a  to  /,  Fig. 
196).  In  this  genus  (Pe- 
ziza),  as  well  as  most 
others  of  this  order,  the 
ascospores  are  always  eight 
in  each  ascus.  At  matur- 


FlG 


FIG.  196. 


Fig.  195. — Sexual  organs  of  Pfsiza  oinphalodes.  The  two  spherical  carpogonia  have 
each  a  crooked  trichogyne,  and  to  each  trichogyne  U  applied  the  swollen  end  of  the 
curved  antheridium.  Much  magnified.— After  Tillage. 

Fig.  196. — Pesiza  convexula.  A,  vertical  section  of  the  whole  plant ;  h,  hymen- 
ium ;  «,  Bterile  tissue  forming  a  margin,  n,  and  giving  off  below  fine  hyphae  which 
pass  into  the  soil,  x  20.  B,  vertical  section  of  n  portion  of  the  hymenium  ;  a  to/, 
asci,  with  ascospore*  in  various  stages  of  devrlopment,  intermixed  with  slender 
paraphyi-es  ;  sh,  sub-hymenial  hyphic.  x  550. — After  Sachs. 

ity  the  ascospores  escape  by  the  rupture  of  the  walls  of  the 
asci,  this  generally  taking  place  at  the  upper  or  free  end. 


288 


BOTANY. 


380. — In  Ascobolus  the  carpogonium  consists  of  a  row  of 
cells  ;  it  develops  from  the  end  of  a  brunch  of  the  mycelium, 
which  becomes  curved  and  divided  by  several  partitions  (c, 
Fig.  197).  On  account  of  its  peculiar  shape  it  is  frequently 
spoken  of  as  the  "  vermiform  body,"  or  scolecite.  From 
another  portion  of  the  mycelium  an  elongated  and  branched 
antheridium  rises,  and  comes  in  contact  with  the  free  end  of 
the  carpogonium  (I,  Fig.  a 

197) ;     after    this    pro-  4        ,.-- 

cess  numerous  filunx  nts 
branch  from  the  mid- 
dle cell  of  the  carpogo- 
nium and  pass  upward, 
eventually  producing 
asci  (s  and  a,  Fig.  197). 
At  the  same  time  an 
abundant  growth  of  hy- 
phse  takes  place  from  the 
mycelium  below  the  car- 
pogonium, and  from  this 
the  greater  part  of  the 
muss  of  the  fruiting 
plant  is  produced ;  it 
also  invests  the  hyme- 
nium,  forming  the  so- 
called  pericarp  which 
encloses  it  (r,  Fig.  197). 

Vertical  branches  of  the  sterile  tissue    also   pass 
hymenial  layer  and  constitute  the  paraphyses. 

381. — The 'asexual  reproductive  bodies  are  but  little 
known,  but  enough  is  known  to  indicate  that  there  is  at 
least  a  conidia-bearing  stage  for  these  Ascomycetes,  as  for  all 
others.  De  Bary  has  shown  that  the  early  stage  of  the  little 
plant  known  as  Peziza  Fuckeliana  is  mould-like  in  appear- 
ance, in  fact  having  been  described  as  a  mould  under  the 
name  of  Polyactis  chirrea.  In  this  stuge  it  grows  upon  dead 
grape  leaves,  sending  its  mycelium  through  the  dead  tissues. 
Its  vertical  hyphae  produce  clusters  of  oval  conidia,  which 
are  much  like  those  produced  in  the  corresponding  stage  of 


Fig.  197. — Diagrammatic  vertical  section  of 
the  spprocarp  of  Ascoboln*  furfuracens.  m,  m, 
mycelium:  c,  carpogouium  ;  /,  untheridinm  ;  «, 
branches  bearing  the  asci, a,  a;  ;>,  />,  pseudo- 
parenchymatous  sterile  tissue  :  r,  r,  cortical 
portion  of  sterile  tissue— above  it  forms  the  so- 
called  pericarp,  which  surrounds  and  encloses 
the  hymenium,  h. — After  Janczewsky. 

into  the 


PYRENOMi'CETES.  289 

Eurotium  and  Penicillin  in.  In  another  species,  Peziza 
fusarioides,  the  conidial  stage  has  been  pretty  certainly  de- 
termined to  be  the  growth  which  was  formerly  supposed  to 
be  a  species  of  Dacrymyces ;  it  consists  of  little  tubercles 
which  contain  slender  linear  bodies  on  branched  threads. 
Bulgaria  sarcoides  is  known  to  bear  conidia  in  an  earlier 
stage,  which  was  formerly  referred  to  the  genus  Tremella 
(Hymenomycetes).* 

(a)  The  principal  genus  of  this  order  is  Peziza,  which  contains  many 
species  ;  they  are  common  on  the  ground  in  forests.  Ascobolm  furfti- 
raceus  is  common  on  cow  dung.  Morchella  esculenta,  the  Morel,  grows 
on  the  ground  in  forests.  It  attains  a  height  of  from  10  to  15  centim- 
etres (4  to  6  inches),  and  bears  its  hymenium  in  shallow  depressions 
of  its  convex  surface. 

(6)  The  Morel  is  edible,  and  is  much  used  for  food  in  some  places. 
According  to  Dr.  M.  A.  Curtis,  some  species  of  Helvella,  also,  are  edible. 

(c)  Peziza  syhatica,  P.  Candida,  aud  Cevangium  Piri  occur  as  fossils 
in  the  Tertiary. 

382.— Order  Pyrenomycetes.  The  plants  of  this  order 
are  parasitic  or  saprophytic  in  habit ;  their  tissues  are  usually 
hard  and  somewhat  coriaceous,  differing  in  this  respect  from 
the  Helvellacece,  which  are  generally  fleshy  ;  they  differ  also 
from  the  plants  of  the  last-named  order  in  having  the  hynie- 
nium  imbedded  in  deep  cavities  (peritliecia)  with  narrow 
openings.  In  other  respects  the  Pyrenomyceies  present  a 
close  similarity  to  the  Relvellacece,  to  which  they  are  doubt- 
less closely  related. 

383. — Their  general  structure  may  be  illustrated  by  a 
couple  of  examples.  In  Claviceps  purpurea,  the  fungus 
which  produces  ergot  on  rye  and  other  grasses,  the  first 
stage  consists  of  a  profuse  growth  of  the  mycelium  in  the 
tissues  and  upon  the  surface  of  the  young  ovary  (s,  A,  and 
B,  Fig.  198).  In  this  stage,  which  is  called  the  Sphacelia 
stage,  it  produces  a  multitude  of  conidia  on  the  ends  of 
hyphse  which  grow  out  at  right  angles  to  the  surface  of  the 
mycelial  mass  (C,  Fig.  198,  b  and  p)  ;  these  conidia  fall  off 
very  easily,  and  quickly  germinate  (Z),  Fig.  198),  giving 
rise  under  favorable  circumstances  to  new  sphacelia,  which 
in  turn  may  produce  conidia,  and  these,  new  sphacelia,  and 

•'See  further,  De  Bary,  <>p.  cit.,  p.  200. 


290 


BOTANY. 


so  on.  The  contact  of  an  infected  head  of  rye  with  an  un  in- 
fected one  is  sufficient  to  communicate  the  fungus  to  the 
latter,  and  doubtless  the  conidia  are  also  freely  carried  by  the 
winds,  and,  to  a  certain  extent,  by  insects.  It  appears  that, 

in  some  cases  at  least, 
the  germinating  co- 
nidia produce,  first, 
short  hyphffi,  which 
bear  a  few  small 
spores  (xporidia,  D, 
Fig.  198,  a;),  which 
th  e  mselves  germi- 
nate, and  then  pro- 
duce the  sphacelia  ;  it 
is  doubtful,  however, 
whether  this  always 
takes  place. 

384.  —  After  the 
conidial  stage,  the 
mycelium  at  the  base 
of  the  ovary  becomes 
greatly  increased,  and 
assumes  a  hard  and 
compact  form  ;  it 
grows  with  a  consider- 
able rapidity,  and  car- 
ries up  on  its  summit 
the  old  sphacelia  and 

the    remains     of     the 

lir.w  d00frnvorl  ,\\-»r\- 
nOW-dCStrOV  Cd  ()\  ill  \ 

tion,    showing  gpliarelia,  s.      0.    transverse   section  /    I   anr\    7?     V\cr     1  Q8"l 

t  hrongh  the  xphnrelia  more  highly  magnified  ;  m,  the  (-1  ana  ^'   *'?•    *W- 

niyoefjnm,  pnrroiindi'd  with  the  hyphw  b,  hearing  co-  The    COmililCt       lioril- 

i.idia  ;  p.  conidiu  fall,  n  off  :  w.  the  vail  of  the  ovliry.  '  )I"P«ltL,     L 

/>,  germinating  conidia,  forming  sporidia,  a:.  A  and  shaped,  and  (lark-COl- 
B  moderately,  6'  and  D  highly  magnifled.-After.  J,  , 

sachs.  ored  body  which  re- 

sults is  called  the  sclerotium  ;  that  which  is  produced  upon 
rye  is  from  one  to  three  centimetres  long  (.4  to  1.2  in.)  and 
from  two  to  six  millimetres  in  diameter  (.08  to  .25  in.)  ;  on 
other  grasses  it  is  usually  of  less  size.  The  sclerotium  occu- 
pies the  position  of  the  displaced  ovary,  and  in  the  autumn 


Fig.  198.—  Clai-iceps  jnirpurea.  A,  young  eclero- 
tium,  o,  with  did  sphacelia,  «  ;  /».  the  apex  of  the  dead 
ovary  of  rye.  S,  upper  part  of  A.  in  longitudinal  sec 


P  YRENOM  YCETE8. 


291 


falls  to  the  ground,  where  it  usually  remains  till  the  follow- 
ing spring,  when  its  hyphae  begin  a  new  growth.  As  a  re- 
sult of  this  new  growth  several  little  branches  shoot  up,  and 
each  forms  a  globular  head  (the  receptacle)  at  its  summit 
(A,  Fig.  199).  Large  numbers  of  flask-shaped  perithecia 
form  in  the  cortical  region  of  the  receptacles  (B,  Fig.  199,  cp}] 
each  contains  many  elongated  asci,  which  rise  from  the  bot- 


Fig.  199. — Clavicep/i  pnrpurea.  A,  a  sclorotinnv(ergot),  c,  forming  the  receptacles 
(eporocarM  ?),  cl.  Ji,  longitudinal  section  of  a  receptacle,  showing  the  perithecia,  cp. 
C,  a  perithecinm,  with  the  surrounding  tissue  ;  cp.  its  orifice;  Ay,  hyphse  of  the  re- 
ceptacle ;  sh,  outer  layer  of  the  receptacle.  -D,  a  single  ascus,  ruptured,  permitting 
the  elongated  narrow  ascospores,  sp,  to  escape.  A  and  li  moderately,  (J  and  D  high- 
ly magnified. — After  Tulasne. 

torn  of  the  cavity  (C,  Fig.  199),  and  themselves  contain 
several  greatly  attenuated  ascospores  (D,  Fig.  199,  sp). 
The  ascospores  germinate  under  proper  conditions,  and  pro- 
duce sphacelia,  thus  completing  the  round  of  life. 

385. — Thus  far  no  sexual  organs  have  been  found,  but 
from  the  general  similarity  of  these  fungi  to  the  Pezizce  and 
other  Helvellaceae,  it  may  be  surmised  that  sexual  organs  and 


292  BOTANY. 

a  sexual  process  precede  the  formation  of  each  receptacle 
which  springs  from  the  sclerotium.  It  may  be,  however, 
that  each  perithecium  is  the  result  of  a  sexual  act ;  in  the 
latter  case  the  single  perithecium  would  be  the  homologue  of 
the  Peziza  cup,  while  in  the  former  the  whole  receptacle  of 
Claviceps  would  be  homologous  to  the  receptacle  of  Peziza. 

386. — As  a  second  illustration  of  the  plants  of  this  order, 
the  Black  Knot  (Sphceria  nwrbosa)  which  attacks  the  plum 
and  cherry  may  be  taken.*  In  the  spring  the  hyphae,  which 
the  previous  year  penetrated  the  young  bark,  multiply 
greatly,  and  finally  break  through  the  bark,  and  "form  a 
dense  pseudo-parenchymatous  tissue."  The  knot-like  mass 
grows  rapidly,  and  when  full  sized  is  usually  from  two  or 
three  to  ten  or  fifteen  centimetres  long  (  8  or  1.2  to  4.  or  6. 
in.),  and  from  one  to  three  centimetres  in  thickness  (.4  to 
1.2  in.) ;  it  is  solid  and  but  slightly  yielding,  and  is  composed 
of  hyphae  intermingled  with  an  abnormal  development  of  the 
phloem  parenchyma  of  the  host  plant ;  bast  fibres  and  modi- 
fied vessels  of  the  wood  also  occur.  Externally  the  knot  is 
at  this  stage  of  a  "very  dark  brownish-green  color,"  and  has 
a  velvety  appearance,  which  is  due  to  the  fact  that  its  surface 
is  covered  with  myriads  of  short,  jointed,  vertical  hyphae, 
each  of  which  bears  one,  two,  or  more  ovate  pointed  conidia 
(Fig.  200,  1).  The  conidia  fall  off  readily,  and  doubtless  are 
important  agents  in  multiplying  the  number  of  these  para- 
sitic growths  ;  they  are  produced  until  the  latter  part  of 
summer,  when  the  hypha  branches  which  bear  them  shrivel 
up  and  disappear. 

387. — During  the  latter  part  of  summer  perithecia  are 
produced  ;  but  the  asci  require  the  greater  part  of  winter  to 
come  to  perfection.  In  February  the  ascospores  are  fully 
ripe.  The  perithecia  at  this  time  are  nearly  globular  in 
shape,  and  are  situated  in  minute  papillae  (3,  Fig.  200)  ;  the 
asci  loosely  cover  the  walls  of  the  perithecial  cavity,  and  are 
intermingled  with  slender  paraphyses  (4,  Fig.  200).  Each 

*  What  follows  is  condensed  from  a  paper  on  "  The  Black  Knot."  by 
Professor  W.  G.  Farlow,  in  the  Bulletin  of  the  Bmsey  Institution,  Vol. 
T.,  p.  440  (1876).  Three  excellent  plates  accompany  the  paper. 


P  TRENOMYL  ETE8. 


293 


ascus  contains  eight  ovate  ascospores,  which  are  two-parted, 
as  is  the  case  in  many  other  members  of  this  order  (5, 
Fig.  200).  The  ascospores  escape  through  a  pore  in  the  top 
of  the  ascus,  and  in  from  three  to  five  days  begin  to  ger- 
minate by  sending  out  a  tube  or  small  hypha ;  sometimes 
two  or  more  hyphae  start  out  from  a  single  ascospore  (6, 
Fig.  200). 

388. — Besides  the  perithecia,  there  are  other  cavities 
found  which  much  resemble  them,  but  which  contain  other 
supposed  reproductive  bodies.  In  one  kind  are  found  the 
stylospores,  which  are  quadrilocular  oval  bodies,  borne  on 
long  stalks  (2,  Fig.  200) ;  they  occur  generally  in  definite 


Fig.  200.— Reproductive  orjrans  of  Spfiasria  mnrbosa.  I,  conidia-bearing  hyphje 
from  a  section  of  the  knot  on  the  cherry,  made  in  May  ;  2,  stylocpores  ;  3,  outline  of 
a  vertical  section  of  a  peritheeimn,  made  in  winter;  4, two  asci.  with  the  contained 
ascospores,  enlarged  from  3  ;  p,  paraphyses  ;  5,  a  ripe  ascospore  ;  6,  two  ascospores 
in  process  of  germination.  All  much  magnified.— After  Farlow. 

patches  on  the  walls  of  the  globular  cavities  above  men- 
tioned. Their  function  is  unknown  ;  but  in  all  probability 
they  are  asexual  reproductive  bodies.  In  other  perithecium- 
like  cavities  slender  filaments  are  produced  ;  these  are  the  sper- 
matia,  and  the  cavities  in  which  they  occur  are  the  sperma- 
gonia.  Still  other  cavities,  much  like  the  preceding,  "  are 
lined  with  short  delicate  filaments,  which  end  in  a  minute 
oval  hyaline  body ; "  these  small  bodies  are  produced  in 
immense  numbers ;  when  they  are  discharged  from  the  cavi- 
ties in  which  they  grow,  they  ooze  out  in  long  jelly-like 
masses.  The  cavities  are  called  pycnidia,  and  the  small 


294  BOTANY. 

bodies  pycnidio-spores.  Neither  the  spermatia  nor  the 
pycnidio-spores  have  been  known  to  germinate  ;  but  from 
the  resemblance  of  the  former  to  those  of  Oucurbitaria, 
Valsa,  and  other  genera  of  this  order,  which  have  been  seen 
to  germinate,*  it  is  quite  certain  that  they,  at  least,  are 
reproductive,  and  that  "they  are  the  agents  for  the  dissem- 
ination of  the  species  to  a  great  distance,"  for  which  they  are 
fitted  by  their  extreme  minuteness.  In  all  probability  the 
pycnidio-spores  have  also  a  similar  function. 

389. — Xo  sexual  organs  have  as  yet  been  observed. 
Doubtless  they  exist  in  the  dense  tissues  of  the  knot,  and 
fertilization  probably  occurs  in  the  spring  or  early  summer, 
while  the  conidia  are  being  produced  on  the  surface  of  the 
young  knot. 

39O. — The  hyphae  of  each  year's  knot  generally  penetrate 
downward  some  centimetres  into  the  uninjured  bark,  and 
remain  dormant  there  until  the  following  spring,  when  they 
begin  the  growth  which  results  in  the  production  of  a  knot, 
as  described  in  paragraph  386. 

(a)  The  Pyrenomycetes  include  a  large  number  of  exceedingly  in- 
jurious fungi  ;  they  often  attack  and  destroy  not  only  plants,  but  also 
insects,  upon  which  their  ravages  are  in  many  cases  very  great. 

(&)  The  classification  is  as  yet  in  gr;'at  confusion.f  The  principal 
genus  is  Sphm  ia,  which  contains  many  species.  Valsa,  Diutrype ,  and 
Hypoxylon  are  other  important  genera. 

(c)  Good  specimens  of  Claviceps  purpurea  may  be  obtained  from 
almost  any  rye-field,  and  more  certainly  from  the  isolated  hunches  of 
rye  growing  here  and  there  in  many  fields.     By  making  repeated  ex- 
aminations soon  after  the  flowering  of  the  rye  the  conidia  may  be 
obtained  ;  and  by  gathering  the  sclerotia  and  burying  them  in  moist 
sand  under  a  bell-jar,  the  receptacles  may  be  grown. 

(d)  Specimens  of  Spfuzria  morbosa  for  study  should  be  gathered  at 
different  times  in  the  season — from  early  spring  to  the  latter  part  of 
the  winter  following.     The  first   gathered  will  be  necessary  to  the 

*  Dr.  Max  Oornn,  in  "  Annales  des  Sciences  Xaturelles,"  Sixtli  Series, 
Vol.  III.,  gives  the  details  of  his  experiments  upon  germinating  the 
apermatia  of  many  Pyrenomycetes.  A  translation  appeared  in  "  Gre- 
villea,"  1877  and  1878,  Nos.  36  to  39. 

f  The  student  may  profitably  consult,  in  studying  this  difficult  order, 
the  finely  prepared  sets  of  "  North  American  Fungi,"  by  J.  B.  Ellis, 
begun  in  1878,  and  still  continuing. 


LICHENE8. 


295 


study  of  the  young  aud  forming  knot,  while  the  succeeding  ones  will 
show  first  the  conidia,  and  then  the  forming  perithecia  and  developing 
asci  and  ascospores.  The  last  gathered  specimens  in  February  will 
show  the  fully  formed  ascospores. 

(e)  Ergot,  which  occurs  on  rye  and  many  of  the  forage  grasses,  is 
poisonous,  producing  gangrenous  sores  when  eaten  in  considerable 
quantities.  It  is  used  somewhat  in  medicine. 

(/)  Xylomites  in  the  Jurassic,  and  Sphceria,  P/tacidium,  Rhytisma 
and  other  genera,  in  the 
Eocene  and  Miocene,  are 
the  fossil  representatives 
of  this  order. 

391  .—Order  Lich- 
enes.  Lichens  agree, 
in  all  the  essentials  of 
their  structure,  with 
the  two  preceding  or- 
ders, HelvellacecB  and 
Pyrenomycetes,  and 
there  can  no  longer 
be  shown  any  good 
reasons  for  not  class- 
ing them  with  the 
latter,  under  the  As- 
corny  cetes. 

392.— The  tissues 
of  lichens  consist  of 
various  aggregations 

Of    Colorless,    jointed  Fig.    SOI.— Transverse 

,        ,                                       ,  Sticta  fuliginosa.     r>,  co 

nypnffl  ;     111     general  face  ;  u.  cortical  layer  o 

,  i      i        v       •      ,  i  or  attaching  fibres ;  m,  medullary  layer,  couioosed  of 

the  hypliae  in  the  COr-  distinct  hyph;e,  many  of  which  are  cut  transversely  ; 

rir-al    -urn-firm    r»f    tlio  0,  layer  ol  green  gonidia.    Eachgonidia  group  is  mir- 

tical    poition    O      me  rounded  by  a  gelatinous  envelope.      X  550. -After 

thallus  are  compact-  Sachs- 

ed  and  developed  into  a  pseudo-parenchyma  (o  and  u,  Fig.  201, 
and  cc,  B,  Fig.  202),  while  in  the  medullary  portion  they  are 
distinct  (m,  Fig.  201,  and  cm,  B,  Fig.  202).  In  all  lichens 
there  occur  numerous  green,  blue-green,  or  brown-green  cells, 
the  gonidia,  which  are  either  scattered  through  the  interior 
(homoomerous),  or  disposed  in  one  or  more  distinct  layers 
(heteromerous)  ;  of  the  former,  Collema  and  Le-ptogium  are 


section  of   the   thallus   of 
cortical  layer  of  the  upper  sur- 
layer  of  lower  surface ;  r,  rhizoid^ 


296 


examples, 'while  of  the  latter  Usnca,  Parmelia  (Fig.  202), 
and  Sticta  (Fig.  201)  may  be  taken  as  illustrations. 


Pig.  202.—Parmflia  aipolia.  A,  a  portion  of  a  tliallu.*  with  two  apothecia,  a/>, 
and  several  spermagonla.  «, «.  J?,  transverse  section  of  thallus  through  an  apotho- 
cium  ;  cc,  cortical  layer  of  pwiido-parenclmiia  ;  </,  </,  sronidia!  layers;  an,  medul- 
lary layer  ;  h.h.  hypotheciuni  ;  t,t.t.t.i\w  hym.-niiini  ;  ft,  asci  (llu-ca-i,  with 
ascogpores.  C,  section  through  three  ipenMgMta,  t.f,*;  rh,rh,  rhixoids.  I>, 
i-torigmata  from  the  interior  of  a  pperinagonium,  hearing  ppermatia,  *•',  *'.— Aftei 
Tulasne. 


LtGHENES. 


29? 


393.^ — In  their  modes  of  reproduction,  also,  lichens  agree 
with  the  before-mentioned  orders  of  the  Ascomycetes.  Like 
them,  they  produce  asci,  containing  ascospores,  spermago- 
uia,  with  their  contained  spermatia,  and  one  or  more  other 
organs  whose  functions  are  supposed  to  be  reproductive. 

394. — The  asci  are  always  developed  from  the  hyphae,  and 
have  no  connection  whatever  with  the  gonidia.  They  arise 
in  most  (but  not  all)  cases  from  the  hyphae  of  the  interior  of 
the  lichen.  It  appears  that  the  particular  hyphae  Avlnch 
produce  asci  differ  from  those  which  are  found  elsewhere  in 
the  lichen  in  being  of  greater  diameter  and  richer  in  proto- 


Fig.  203.— Vertical  section  through  the  young  apothecinm  of  Lecanora  subfmca 
(partly  diagrammatic) ;  h,  h,  hymenium,  composed  of  (1)  paraphyses,  which  de- 
veloped from  the  ordinary  hyphie,  and  (2)  the  young  asci  in  various  stages  of  de- 
velopment ;  sh,  .-iscophorous  hyphie,  from  which  the  asci  develop;  e,  excipulum— i.e., 
the  layer  of  hyphse  upon  which,  or  above  which  the  ascophorous  hyphae  are  borne  ; 
r,  r,  cortical  layer  of  thallus  ;  m,  medullary  portion  of  thallus  ;  g,  the  gonidia.  X  190. 
—After  De  Bary. 

plasm.  The  asci  are  developed  from  vertical,  club-shaped 
branches,  which  penetrate  between  narrow,  vertical  branches 
(paraphyses)  of  the  ordinary  hyphae  (Fig.  203).  In  many 
cases  they  are  collected  in  a  disc-like  surface,  forming  an  ex- 
posed hymenium  (gymnocarpous  lichens),  while  in  other  cases 
they  are  in  the  interior  of  cavities  (perithecia),  whose  walls 
they  line  (angiocarpous  lichens).  The  ascigerous  fructifica- 
tion is  in  either  case  technically  called  an  apothecium. 

395. — The  spores  arise  in  the  asci  exactly  as  in  the  case  of 
Peziza  and  other  Ascomycetes  previously  described  :  that  is, 
they  are  formed  simultaneously  by  the  condensation  of  the 
protoplasm  about  certain  points  in  the  interior  of  the  young 


298 


BOTANY. 


ascus  (the  so-called  free  cell  formation).  Usually  there  is  a 
considerable  quantity  of  the  unused  protoplasm  left  over 
after  the  ascospores  are  fully  formed  (Fig.  204.  a,  b,  c).  The 
usual  number  of  ascospores  is  eight  (Figs.  202,  203,  204), 
although  in  exceptional  genera  they  range  from  one  or  two 
(  Umbilicaria)  to  a  hundred  or  more  (Badrospora,  and  other 
genera).  They  are  frequently  septate,  sometimes  being  di- 
vided into  two  portions  —  e.g.,  Parmelia  (Fig.  202)  —  or 
many,  as  in  Collema  Urceolaria,  etc.  In  the  gymnocarpous 
lichens  the  ascospores  escape  directly  into  the  air.  and  this 
they  generally  accomplish  with  such  force  as  to  be  projected 
some  millimetres  ;  in  the  aiigio- 
carpous  genera  they  first  escape 
into  the  cavity  of  the  perithe- 
cium,  from  which  they  pass  out 
through  an  opening  in  its  apex. 

396.  —  In  germination  the  as- 
cospore  commonly  sends  out  a 
germinating  tube,  which  is  a 
growth  from  the  endospore  ;  it 
develops  directly  into  a  hypha, 
and  becomes  branched  and  sep- 
tate. Bi-  or  multilocular  asco- 
spores  usually  send  out  a  germi- 
nating  tube  from  each  cell.  In 

the  senera  with  very  lar§e  asc°- 

spores—  e.g.  ,  Megalospora,  Per- 
tusaria,  etc.  —  the  germination  takes  place  in  a  way  somewhat 
different  from  that  just  described.  In  the  endospore  a 
great  number  of  cavities  or  canals  form  (g,  Fig.  205),  from 
each  of  which  there  grows  out  a  germinating  tube  (d,  Fig. 
205)  ;  these  many  tubes  elongate  into  hyphae,  and  become 
septate  and  branched  (/,  Fig.  205). 

397.  —  In  addition  to  the  apothecia,  with  their  contained 
ascospores,  there  are  other  organs  which  contain  bodies 
which  are  probably  reproductive  in  their  nature.  The 
best  known  of  these  are  the  spermagonia  (Fig.  202,  A,  .<?, 
and  Fig.  206),  which  are  small  cavities,  usually  found  upon 
the  same  thallu.s  as  the  apothecia;  they  contain  branched 


DeBar>' 


LICHENES. 


299 


threads  (sterigmata),  which  line  the  inside  of  the  wall  (Fig. 
202,  D]  ;  upon  the  sterigmata  are  borne  large  numbers  of 
minute  cells  (the  spermatia},  which  fall  off  and  are  per- 
mitted to  escape  through  the  small  opening  at  the  apex  of 
the  spermagoniurn.  It  is  unknown  whether  these  germinate 
or  not  ;  some  botanists  have  supposed  them  to  be  sexual  in 
their  nature — hence  their  name,  spermatia ;  the  recent  in- 
vestigations of  Stahl,  to  be  referred  to  below,  seem  to  indi- 


Fig.  205.— Germination  of  the  spores  of  lichens,  a,  ripe  ascospore  of  Megal- 
Oitpora  qffliiin  ;  b  and  c,  successive  stages  of  germination,  seen  in  optical  section  ; 
d,  still  later  staire  of  germination,  seen  in  perspective,  e,  beginning  of  germination 
of  ascospore  of  Ochrolechia  pallesceng  ;  f,  the  same  at  a  much  later  stage,  show- 
ing the  many  young  hyphte.  much  less  magnified,  g,  half  of  an  ascosponi  of  Per- 
tusurla  ceuthocarpa  ?  seen  in  optical  section,  showing  the  pores  in  the  endospore 
through  which  the  hyphre  p  iss  out.  The  exospore  is  shaded  in  the  figure.  /  X 
190,  the  others  x  390. -After  De  Bary. 

cate  the  truth  of  the  theory  that  they  are  the  male  sexual 
elements ;  on  the  other  hand,  their  analogies  to  the  similar 
organs  of  Helvellacece  and  Pyrenomycetes  point  rather  to 
their  conidial  nature. 

Still  other  cavities  (pycnidia)  occur,  in  which  spore-like 
bodies  are  found,  differing  in  size  and  other  characters  from 
the  spermatia. 


300 


BOTANY. 


398. — Until  StahFs  researches*  showed  the  existence  of 
sexual  organs  in  Collema,  they  were  entirely  unknown  among 
lichens.  He  discovered,  deeply 
imbedded  in  the  tissue  of  the 
plant,  an  organ  composed  of  a 
spirally  coiled  hypha- branch,  and 
a  vertical  septate  portion,  which 
rises  to,  and  projects  above,  the 
surface ;  the  spirally  coiled  por- 
tion he  called  the  ascogonium, 
and  the  vertical  portion  the  tri- 
chogyne.  The  whole  he  regarded 
as  a  species  of  carpogonium  (Fig. 
207,  A,  c,  and  d).  He  observed 


Fig.  20fi.-Vertical    section  of 
mall 


1  portion  of  the  thallus  of  Col- 
Uma    Jacobcefolium,   showing    the 
colorless  branching  and  jointed  hy-    gpemiatia    adhering     to    the    pro- 
phse,  the  Nostoc-like  gonidia,  and  a     i  -r 

spermagonium,  from  which  gperma-    lecting      portion    of      the     tricho- 
tfa  are  escaping.    Magnified.-After  J 

Tuiasne.  gyne  ;  some  of  these  united  them- 

selves to  the  trichogyne  by  means  of  a  tube  (C,  Fig.  207). 
The  result  of  this  coalescence  was  the  withering  and  disap- 
pearance of  the 
cells  of  the  tricho- 
gyne, and  the 
growth  and  devel- 
opment of  the  as- 
cogonium. The 
latter  process  takes 
place  as  follows  : 
"  The  cells  of  the 
ascogonium  first  of 
all  increase  in  size, 
and  then  undergo 

,.    .   .  Fig.  207. — Sexual  organs  of  Colleina  >ntcrophyllvm.  A, 

division  ;     as    a    re-  section  of  thalli..-*;  a.  a,  hyphte:    ft,  b,  the  No«toc-like 

suit    of    this, 

crrvifnl  t-    U,  coalescence  or  a  gpermatitim, 

spiral  arrangement  Aii  the  figures  magnified,  B  and  c 

of    the    cells    be-  After8t»hl- 

comes  less  and  less  conspicuous,  for  the  cells  gradually  sepa- 

*  "  Ueber  die  Geschlechtliche  Fortpflanzunjf  der  Collemaceen,"  1877 
(On  the  Sexual  Organs  of  tin-  Colleni  in-a-).  A  brief  synopsis  of  Stahl's 
results  appeared  in  the  Qr.  Jour,  of  Mic.  Science,  October,  1878. 


,-,       gor.idia  ;  c.  ascogonium  ;  <7,  the  exst-rted  trichogyne.    B, 
tne  the  spermatia,  b,  surrounding  theexMTted  trichoayae,  a. 
coalescence  of  a  Bpermatium,  6,  with  trichogyne,  a. 
-  amuch  more  than  A— 


LIGHJSNm.  301 

rate  from  one  another.  Whilst  these  changes  have  been 
taking  place  in  the  ascogonium,  it  has  become  invested  by  a 
dense  felt- work  of  hypha?,  formed  by  the  active  growth  of 
the  hyphae  of  the  thallus.  From  this  investing  layer  hyphse 
grow  inward  between  the  separating  coils  of  the  ascogo- 
nium, and  bear  paraphyses,  which  form  the  rudimentary 
hymenium.  At  the  same  time  outgrowths  have  been 
formed  from  the  cells  of  the  ascogonium,  which  either  are 
asci,  or  grow  into  hyphal  filaments,  which  bear  asci  as 
lateral  branches.  The  asci,  whether  derived  directly  or  in- 
directly from  the  cells  of  the  ascogonium,  come  to  lie  in  the 
hymenium  among  the  paraphyses."  Thus  the  apothecium 
is  partly  developed  from  the  carpogonium,  and  partly  from 
the  hyphse  of  the  thallus,  agreeing  in  this  with  what  is  now 
known  to  be  the  mode  of  formation  of  the  corresponding 
parts  of  some,  at  least,  of  the  Helvellacece. 

Whether  there  are  similar  sexual  organs  in  other  lichens, 
is  at  present  unknown  ;  probably,  when  discovered,  they  will 
be  found  to  bear  some  resemblance  to  those  of  Collema,  just 
described  ;  but  it  is  altogether  likely  that,  instead  of  fertili- 
zation taking  place  by  means  of  free  male  elements  (sper- 
matia),  it  will  be  shown  to  be  more  nearly  like  that  now 
known  in  Peziza  or  Ascobohis. 

399.— The  Gonidia.  The  gonidia  of  lichens  are  of  so 
much  importance  that  they  demand  a  somewhat  extended 
notice.  As  above  stated  (paragraph  392),  they  are  green  or 
greenish  cells,  or  roAvs  of  cells,  Avhich  occur  either  distributed 
irregularly  through  the  tissue  of  the  lichen-thallus  (the  ho- 
moomerous  lichens),  or  in  different  layers  or  regions  (the 
heteromerous  lichens).  These  green  bodies  are  of  different 
forms  in  different  groups  of  lichens,  while  in  nearly  related 
species  they  are  often  exactly  alike.  They  may  consist  of 
isolated  cells,  or  groups  of  cells,  as  in  most  fruticose  or  folia- 
ceous  lichens  (e.y.,  Parmelia,  Fig.  202,  Sticta,  Fig.  201, 
Splmrophorus  and  Usnea,  Fig.  208),  while,  on  the  other 
hand,  they  may  be  made  up  of  rows  or  chains  of  cells 
(e.g.,  Lecanactis  and  Grapliis,  Fig.  209,  Mallotium,  Fig. 
210,  and  Collema,  Figs.  206  and  207).  They  are  knoAvn  to 
reproduce  by  the  division  (fission)  of  their  cells,  and,  in 


302 


BOTANY. 


some  cases  at  least,  when  free  from  the  lichen-thallus,  by 
the  production  of  zoospores. 

Their  connection  with  the  hyphan  is  sometimes  by  the 
prolongation  of  a  short  branch  from  the  latter,  which  passes 
to  each  gonidial  cell  (Fig.  208) ;  in  other  cases  the  connec- 
tion is  with  one  cell  of  a  row,  as  in  Plectospora,*  where  the 
connection  may  be  with  the  terminal  cell  of  the  row,  or  with 
any  of  the  intermediate  ones ;  in  either  case,  the  cell  to 
which  the  hypha-branch  is  attached  is  considerably  larger 
than  the  others  in  the  row.  Schwendener  describes!  a  con- 


FIG.  208. 


FIG.  209. 


Fig.  208.— Gonidia  of  different  lichens,  a  to  «,  of  Parwrlia  titiacea,  showing  a,  6, 
and  e,  the  attached  hyphu-,  X  390 ;  A  of  Usnea  barbata.  with  attached  hypha,  X 
700  ;  g,  of  Sphcerophor'us  globiferiis,  with  attached  hypha,  x  390.— After  De  Bary  and 
Schwendeiier 

Fig.  209.-Gonidia.  a,  a,  of  Lecanactis  illecebrosa ;  b,  l>,  of  Qraphis  swipta.— 
After  De  Bary. 

nection  which  he  has  seen  in  certain  gelatinous  lichens,  in 
which  two  and  three  short  branches  pass  off  from  the  same 
hypha,  and  unite  with  the  cells  of  one  gonidial  chain. 
TronbJ  confirms  Schwendener's  statement,  saying  that  he 

*  See  De  Bary's  "  Morphologic  und  Physiologic  der  Pilze,  Flechten," 
etc.,  p.  264. 

f  "  Die  Flechten  als  Parasiten  der  Aljren,"  1873. 

j  Dr.  Melchior  Treub,  "  Onderzoekingen  over  de  Natuur  der  Liche- 
nen."  1873. 


LICHENES. 


303 


has  "succeeded  many  times" in  finding  gonidia  so  connected 
to  the  hyphae  by  more  than  one  branch. 

400. — With  regard  to  the  origin  of  gonidia,  Fries  asserts 
that  the  hypha-branches  swell  up  at  their  ends,  become  glob- 
ular, and,  after  a  while,  filled  with  green  contents.*  He, 
however,  does  not  speak  of  any  observations  of  his  own  upon 
Avhich  he  bases  his  statement.  Berkeley!  likewise  regards 
them  as  developed  from  the  mycelium,  but  made  no  observa- 
tions which  can  be  considered  conclusive.  Speerschneider's 
observations, \  in  1853  to  1857,  along  with  those  of  Bayr- 


Fig.  210. — Mallotixm  (or  Leptogium)  Ifi/tleiibrandii.  a,  vertical  section  through  the 
thallnn,  w,  the  under  side,  x  190  ;  6,  portion  of  a  very  thin  section  near  the  under 
side,  showing  three  gonidia  chains,  two  hyphfe,  a  portion  of  the  lower  limitary  tissue, 
and  two  large  and  several  small  hairs,  which  are  organs  of  attachment,  x  390. — After 
De  Bary. 

hoffer,§  some  years  earlier,  appear  to  be,  in  reality,  the  ones 
upon  which  the  view  that  gonidia  develop  from  the  hyphae 
depends  ;  their  statements  appear  to  have  been  accepted  and 
repeated  by  lichenologists  without  sufficient  inquiry.  The 
other  errors  of  observation  and  interpretation  made  by  these 
observers  render  their  testimony  upon  the  question  of  the 
origin  of  the  gonidia  of  doubtful  value.  Schwendener,  in 


*  "  Lichenograpliia  Scandinavica,"  1871. 

f  "  Introduction  to  Cryptogamic  Botany,"  1857. 

t  In  Botanische  Zeitung,  1853,  1854,  1855,  1857. 

§  "  Einiges  uber  die  Lichenen  und  deren  Befruchtung,"  1851. 


304 


BOTANY. 


reviewing  the  subject,  affirms  that  the  actual  development  of 
a  gonidium  from  the  end  cell  of  a  hypha  has  not  been  ob- 
served. Nylander  even  goes  so  far  as  to  declare  that  in  no 
case  do  the  filaments  themselves  give  birth  to  gonidia,  but 
that  they  "have  their  origin  in  the  parenchymatous  cortical 
cells  which  are  observed  on  the  prothallian  filaments  of  ger- 
mination."* 

401. — The  recent  observations  of  Dr.  Minks,f  if  con- 
firmed, will  put  to  rest  the  question  as  to  the  origin  of  go- 
nidia. He  studied  the  small  green  cells  sometimes  called  mi- 
crogonidia,  and  makes  the  announcement  that  they  originate 
in  the  interior  of  the  cells  of  every  portion  of  the  lichen- 
thallus,  viz.,  the  cortical  and  medullary  cells,  the  paraphy- 

ses  and  young  asci,  and 
even  the  spores  and 
spermatia.  The  proto- 
plasm in  the  cells  forms 
an  axial  column,  which 
becomes  broken  up  into 
rounded  bodies  of  a  pale 
greenish  color ;  these 
finally  become  covered 
by  cell-walls  and  after- 
ward escape  from  the 
mother-cell  as  free  mi- 
crogonidia.  He  asserts 
that  intermediate  forms  of  all  degrees  are  to  be  met  with  be- 
tween microgonidia  and  gonidia.  Dr.  Muller,in  making  simi- 
lar observations,  arrived  at  the  same  conclusion  J  as  to  the 
origin  of  the  microgonidia. 

The  third  view  as  to  the  origin  of  gonidia  is  so  intimately 
connected  with  the  question  of  the  real  nature  of  the  gonid- 
ium and  its  functional  relation  to  the  hypha?,  that  it  can 
only  be  explained  by  taking  these  into  consideration. 

*  In  Flora,  1877,  p.  256,  as  quoted  in  Revue  Mycofagique,  p.  4, 1879, 
and  in  "Grevillea,"  1879,  p.  91. 

f  For  accounts  of  these  observations  see  Flora,  1878,  Revue  Mycolo- 
yique,  1879,  and  American  Journal  of  Science  and  Arts,  1879,  p.  254. 

J  Flora,  1878. 


Fig.  211.—  Soredia  of  Usnea  barbafa.  A,  sore- 
dium,  consisting  of  one  gonidium  covered  with 
hyphae  ;  B.  of  many  gmiidia  formed  by  division  ; 
C,  the  gonidia  pepuratt- d  by  hyphte  ;  I)  and  E,  the 
soredia  developing  into  new  lichen  plants.  X 
500.- After  Schwendcner. 


LICHENE8.  305 

4O2. — The  gonidia  sometimes  escape  from  the  thallus  of 
the  lichen  surrounded  with  a  few  hyphae  (Fig.  211)  ;  these 
are  called  soredia.  Under  favorable  circumstances  they  may 
give  rise  to  new  lichens,  and  hence  have  been  looked  upon 
by  some  as  asexual  organs  of  reproduction.  Soredia  are, 
however,  rather  of  the  nature  of  buds  or  gemmae,  which, 
under  certain  circumstances,  become  detached.  Their  pro- 
duction is,  to  a  certain  extent,  accidental. 

(a)  1.  The  Nature  of  Gonidia.  Until  recently,  the  gonidia  of 
lichens  have  been  generally  regarded  as  accessory  reproductive  bodies. 
De  Bary,*  however,  in  studying  the  Colleuiacese,  and  noting  the  remark- 
able resemblance  between  their  gonidia  and  certain  algae,  came  to  the 
following  conclusion:  "  Either  the  lichens  in  question  are  the  perfectly 
developed  states  of  plants  whose  imperfectly  developed  forms  have 
hitherto  stood  among  the  algae  as  the  Nostocaceae  and  Cliroococcaceae  ; 
or  the  Nostocaceae  and  Chroococcaceae  are  typical  algae  which  assume  the 
form  of  Collema,  Ephebe,  etc.,  through  certain  parasitic  Ascomycetes 
penetrating  into  them,  spreading  their  mycelium  into  the  continuously 
growing  thallus,  and  becoming  attached  to  their  phycochrome-contain- 
ing  cells."  Schwendener.f  Reess.J  and  Bornetg  have  taken  up  the 
second  theory  in  the  above  alternative,  and  extended  it  to  all  lichens. 
Schwendener,  who  first  made  the  definite  statement  of  the  theory,  holds 
that  every  lichen  is  a  colony  composed  of  a  parasitic  fungus  on  the  one 
hand,  and  a  number  of  low  algae  on  the  other  ;  the  former,  which  pro- 
duces the  asci,  spermatia,  and  other  reproductive  bodies,  is  nourished 
by  the  latter,  which  constitute  the  gonidia  of  the  lichen. 

A  lichen,  according  to  this  view,  is  not  an  individual  plant,  but  rather 
a  community  made  up  of  two  kinds  of  individuals  ;  and  the  gonidia  are 
only  the  temporarily  imprisoned  algae,  which  furnish  nutriment  to  the 
parasitic  fungus.  The  fungus  parasite  does  not  differ  in  any  essential 
character  from  those  of  the  two  higher  orders  of  the  Ascomycetes. 
Leville,  in  speaking  of  lichens  and  the  ascomycetous  fungi,  said.J 
"  I  find  the  distinctions  to  be  so  trifling,  that  I  have  always  regretted 
that  these  vegetables  should  not  be  placed  under  one  head.  The  para- 
physes,  therae  (asci),  and  spores  are  identical." 

*  "  Morphologic  und  Physiolo,;ie  d«r  Pilze,  Flechten,  und  Myxomy 
ceten,"1865,  p.  291. 

f  Dr.  S.  Schwendener  :  "  Untersuclmngen  iiber  den  Flechtenthallus," 
1868,  and  <rDie  Algentypen  der  Flechtengonidien,"  18G9. 

\  Professor  Max  Reess  :  "  Ueber  die  Entstehung  der  Flechte  Collema 
glaucescens,"  etc,  1871. 

§  Dr.  E.  Bornet  :  "  Recherches  sur  les  Gnnidies  des  Lichens,"  1873. 

U  A  letter  to  Decaisne,  as  given  in  Le  Maout  and  Decaisne's  "  Traite 
Generate  de  Botanique,"  1868. 


300  BOTANY. 

2.  Schwendener  has  shown*  that  the  gonidia  may  be  referred  to  well- 
known  groups  of  alga?,  some  of  which  belong  to  the  Zygosporese,  while 
others  belong  to  the  Protopliyta.     Thus  the  gonidia  of  Cottema,  Lepto- 
gium  (including  Mallotium),  Pdtigera  and  some  other  genera,  are  iden- 
tical with  Nostocaceae  ;  those  of  Omphalaiia  and  others,  with  Chroo. 
coccaceae  ;  those  of  Chraphis,  Ve> rucaria,  etc.,  witli  Chroolepideae  (re- 
lated to  Confenn  and  Cladophora) ;  those  of  Usnea,  Cladonia,  Physcia, 
Parmdia,  and  most  higher  lichens  with  Palmellacese.     Tlie  gonidia  of 
some  other  lichen  genera  are  referred  to  still  other  alga  groups. 

3.  When  gonidia  are  dissected  out  from  the  lichen-thallus  they  are 
capable  of  independent  existence  ;  and  there  can  be  no  doubt  that  (as 
De  Bary  intimated)  many  of  the  forms  regarded  as  algae  are  identical 
with  gonidia.f     With  these  facts  before  us,  it   can  scarcely  be  doubted 
that  the  mode  of  origin  described  by  Speerschneider  and  Bayrhoffer  is 
incorrect.     There  cannot  now  be  shown  any  good  evidence  that  the  go- 
nidia develop  from  tlie  hyphae  with  which  they  are  seen  to  be  in  contact. 
The  connection  between  hyphte  and  gonidia  is  doubtless  one  which  takes 
place  after  the  origin  of  the  latter.     The  two  remaining  views — i.e., 
Schwendener's  and  Minks' — agree  upon  this  point,  and  in  both  the  idea 
of  a  genetic  connection   between  gonidium  and  the  hypha-filament  in 
contact  with  it  is  rejected.     These  two  theories,  however,  differ  radi- 
cally in  this,  that  while,  on  the  one  hand  the  gonidia  are  regarded  as 
true  lichen-cells,  on  the  other  they  are  held  to  be  algae  belonging  to  en- 
tirely different  thallophytic  groups. 

4.  It  must  at  once  be  evident  to  any  one  that  the  actual  relation  of 
the  hyphal  portion  of  the  lichen  to  the  gonidia  is  the  same  whether  the 
origin  of  the  latter  be,  as  asserted  by  Minks,  within  the  hyphae,  or  en- 
tirely independent  of  them,  as  imuntained  by  Schwendener.     Any  con. 
nection  which  subsists  between  these  two  can  be,  under  the  circum- 
stances, of  only  one  kind,  namely,  that  of  a  greater  or  less  degree  of 
parasitism.    It  makes  no  difference  to  show  that  tlie  gonidia  are  derived 
from  the  hyphae  themselves,  for  they  are  (it  is  said)  set  free  after  their 
formation  in  the  mother-cell  ;  now  any  subsequent  connection  of  these 
green  cells  with  the  hyphae  cannot  possibly  have  any  other  meaning 
than  that  the  latter  derive  nourishment   from  them.     The  only  differ- 
ence between  the  two  theories  may  be  expressed  in  this  way  :  according 
to  the  one,  the  imprisoned  slaves  which   furnish  nourishment  for  the 
hyphal  master  are  members  of  entirely  different  groups  of  the  vegetable 
kingdom  ;  while  according  to  the  other,  the  slaves  are  the  offspring  of 
the  hyphal  master  which  imprisons  them.     In  the  first  the  gonidia  are 


*  "  Die  Algentypen  der  Flechtengonidien,"  1869. 

t  This  was  lonir  since  shown  by  Itzijrsohn — Hotaniscke  Zeitutig,  1854, 
by  Hicks—  Qr.  Jour,  of  Mic.  Science,  1861 ,  and  by  Famintzin  and  Baranet- 
sky — Botanische  Zeitung,  1867  ;  Nylander  also  arrived  at  the  same  con- 
clusion with  regard  to  the  gonidia  of  Collema—  Flora,  1S08. 


LR'HENES.  30? 

slaves  not  at  all  related  to  the  hyphae  ;  in  the  other  they  are  produced 
by  them,  and  after  a  brief  period  of  freedom  are  fastened  upon,  and 
«ompelled  to  do  service  for  the  hyphae  which  produced  them. 

It  is  impossible  to  decide  between  these  two  theories  until  further  in- 
vestigations shall  determine  the  truth  or  falsity  of  Dr.  Minks'  state- 
ment as  to  the  origin  of  microgonidia.  It  must,  however,  be  said,  that 
the  view  which  appears  to  be  most  in  accord  with  what  we  now  know 
of  plants,  is  that  taken  by  Schwendener. 

(6)  1.  Cultures  of  lichens  have  been  made  by  many  observers, 
especially  by  Bornet,  Reess,  and  Treub.  The  latter  made  an  extended 
series,  from  which  the  following  details  of  methods  are  condensed. 
Spores  may  be  secured  for  germination  by  placing  freshly  gathered 
lichens  upon  plates  covered  with  well-moistened  glass  slips,  and  keep- 
ing them  under  a  bell-jar  for  from  twelve  to  twenty-four  hours,  at  the 
end  of  which  time  a  number  of  spores  will  be  found  on  the  slides. 

2.  The  spores  may  be  left  upon  the  slides  and  allowed  to  remain  in  a 
moist  atmosphere,  as  in  a  bell-jar.     Others  may  be  placed  upon  very 
thin  pieces  of  the  bark   upon  which  the  lichens  naturally  grow.     Still 
others  may  be  made  to  grow  in  the  presence  of  a  small  quantity  of  the 
ash  of  the  same  species  of  lichen. 

3.  A  too  copious  supply  of  moisture  is  unfavorable  to  the  successful 
germination  of  the  spores.    If  the  conditions  are  favorable  germination 
will  begin  in  from  two  to  eight  days.     In  about  a  month  after  sow- 
ing, the  protoplasm  of  the  spore  becomes  in  great  part  used  up  in  the 
formation  and  elongation  of  the  germinating  filaments.    It  always  hap- 
pens that  the  growth  of  the  hyphae  from  the  spores  ceases  soon  after  the 
exhaustion  of  the  protoplasm,  unless  the  hyphae  come  in  contact  with 
algae  of  the  proper  kind,  or  with  gonidia. 

4.  An  interesting  culture  may  be  made  by  repeating  Hornet's  exper- 
iment, as  follows:  He  placed  on  fragments  of  bark,  previously  boiled 
to  kill  all  other  germs,  and  also  ou  pieces  of  limestone  freshly  broken, 
a  layer  of  Protococcus  viridis  scraped  off  of  a  damp  wall,  and  to  this 
added  the  spores  of  Tlidoschistes  parielinus.     In  about  a  fortnight  the 
hyphae  were   seen  to   be  large  and  ramified  ;  wherever  they  came  in 
contact  with  cells  of  the  Protococcus  they  adhered  either  directly  or  by 
means  of  lateral  branches.     Bornet  made  at  the  same  time  parallel  cul- 
tures, without,  however,  bringing  the  germinating  spores  into  proximity 
to  Protococcus ;  the  growth  was  much  less,  and  in  no  case  did  he  get 
any  evidence  that  the  hyphae  themselves  formed  gonidia. 

5.  Treub  modified  Bornet's  culture  by  using,  in  some  of  his  experi- 
ments, the  artificially  isolated  gonidia  of  one  species  of  lichen — for  ex- 
ample, of  some  species  of  Ramattna — and  the  spores  of  a  different  one,  as 
Thelosehistes  parielinus.     He  also  used  glass  slides  for  his  cultures, 
whether  with  gonidia  or  free  algae,  taking  the  precaution,  however,  to 
allow  the  drop  of  water  in  which  the  spores  and  gonidia  were  placed 


308 


BOTANY. 


to  completely  evaporate  before  placing  in  the  moist  chamber.  By  tak- 
ing precautions  to  keep  out  moulds,  by  supplying  the  moist  chamber  with 
air  passed  through  one  or  two  plugs  of  cotton-wool,  he  succeeded  in 
continuing  the  growth  of  the  hyphae  for  three  months,  at  the  end  of 
which  time  the  algse  were  surrounded  by  a  good  number  of  branches 


FIG.  213. 


Fig.  MZ.—Usnfabarbafa,  nat.  size,    a,  a,  apothecia  ;  f,  disk  by  which  it  is  attached 
to  the  bark  of  a  tree.— After  Sachs. 
Fig.  213.— Stiota  pulmonacea,  nat.  size.    «,  a,  apothecia.— After  Sachs. 

of  the  hyphae,  many  of  which  had  firmly  attached  themselves  to  the 
cells  of  the  algae. 

(c)  The  classification  of  lichens  is  by  no  means  settled. 

The  arrangement  which  is  followed  in  this  country  ia  that  of  Profes- 
sor Tuckerman.*  He  divides  the  order  into  five  tribes,  as  follows: 

TRIBE  I.  PARMELIACEI. 

Apothecia  rounded,  open,  scutelliforin,  contained  in  a  thalline  exciple. 

Family  1.  Usneei.  Rocce.Ua,  Ramalina,  Dactylina,  Cetraria,  Ever- 
Jiia,  Uanea  (Fig.  212),  Alec  o>ia.  Roccella  <inctoria  nnd  other  species  of 
the  genus  furnish  the  dye  known  as  orchil,  and  chemical  test  "  litmus." 
Cetraria  islandica,  the  Iceland  moss,  is  used  botli  as  a  food  and  a  medi- 


*  Edw.  Tuckerman  :  "  Genera  Lichenum  ;  An  Arrangement  of  North 
American  Lichens,"  1872, 


LIGHENES. 


309 


Speet  schneidera,  Theloschixtes,  Parmelia 
From  Parmelia  parietina  fine  dyes  have 


Umbilica- 


cine.     Species  of  Evernia  are  sometimes  used  for  furnishing  yellow 
dyes. 

Family  2.  Parmeliei. 
(Fig.  202),  Physcia,  Pyxine. 
been  obtained. 

Family  3.    Umbilicariei. 
ria. 

Family  4.  Peltigerei.  Sticta  (Fig. 
213),  NepJiroma,  Pdtigera,  Solorina.  Stic- 
ta  pulmonacea  was  formerly  used  in  medi- 
cine, but  it  bas  fallen  into  disuse,  except- 
ing with  quacks. 

Family  5.  Pannariei.     ffeppia,  Pan-      ^  zu.-Collema  pulpotwn, 
naria  slightly  magnified,  showing   the 

Family  6.    Collemei.     BpMbe,  Lich-  *P°the™-A«- Sachs- 
ina,   Synalissa,    Ompkalaria,   Col'ema  (Fig.  214),   Leptogium,   Hydro- 
thyria. 

Family  7.  Lecanorei.     Placudiwm,  Lecanora,  Rinodina,  Pertusa- 
1-ia  (Fig.  215,  C),  Couotrema,  Dirina,  Gyalecta,  Urceolaria,  Thelotrema, 

Oyrostomum.  Lecanora  tarta- 
rea  furnishes  a  dye,  and  L. 
esculenta,  of  Asia  Minor,  sup- 
plies a  valuable  food ;  it  is 
sometimes  "  carried  up  by 
whirlwinds  and  deposited  after 
traversing  the  air  for  many 
miles,  giving  rise  to  stories  of 
the  miraculous  descent  of  food. 
A  few  years  since,  in  a  time  of 
great  scarcity  at  Erzerouin,  a 
shower  of  these  lichens  fell 
most  opportunely,  to  the  great 
relief  of  the  inhabitants."* 

TRIBE  II.  LECIDEACEI. 

Apothecia  rounded,  open,  pa- 
telliform,  contained  in  a  proper 
exciple. 

Family  1.  Cladoniei.    Ste- 
«*"*>»•  ^ophorus,  Cladonia. 
ifled;  C,  Pertxxarui  Wnlftni,  sliditly  ma«-   Ghidonw     rangiferiita    is     tlie 
hlfled,  on  a  piece  of  old  wood.-Afier  Sach,.      . .  Reindeer  moss  »  of  tbe  Amic 

regions  ;  it  furnishes  a  valuable  food  to  the  reindeer. 


Berkeley  :  "  Introduction  to  Cryptogainic  Botany,"  p.  383. 


310  BOTANY. 

Family  2.  Coenogoniei.     Ceenogonium. 

Family  3.  Lecideei.  Bceomyces,  Biatora,  Heterothecium,  Lecidea, 
Buellia. 

TRIBE  III.  GRAPHIDACEI. 

Apothecia  of  various  forms,  frequently  lirelliform,  in  a  proper  ex- 
ciple.  Thallus  crustaceous. 

Family  1.  Lecanactidei.     Lecanactis,  Platygrapha,  Melaspilea. 

Family  2.  Opegraphei.  Opegrapha,  Xylographa,  Qraphis  (Fig. 
215,  A), 

Family  3.  Grlyphidei.     Chiodecton,  Olyphis. 

Family  4.  Arthoniei.     Arthonia,  Mycoporum. 


TRIBE  IV.  CALICIACEI. 

Apothecia  turbinate-lentiform  or  globose,  frequently  stipitate,  mar- 
gined  by  a  proper  exciple,  the  disk  breaking  up  into  naked  spores, 
which  form  a  compact  mass. 

Family  1.  Sphserophorei.     Sphcerophorus,  Acroscyphus. 

Family  2.  Caliciei.     Acolium,  Cahcitim,  Contocybe. 

TRIBE  V.  VERRUCARIACEI. 

Apothecia  globose,  in  a  proper  exciple,  becoming  pertuse  with  a  pore. 

Family  1.  Endocarpei.     Endocarpon,  Normandina. 

Family  2.  Verrucariei.  Segestria,  Staurotfiele,  Trypethelium,  Sa- 
gedia,  Verrucaria,  Pyrenula,  Pyrenastrum,  Strigula. 

(d)  Fossil  lichens  are  extremely  rare,  only  a  few  Tertiary  species  of 
modern  genera  being  recorded. 

403.— Order  Uredinese. — The  Uredineae  are  related  to  the 
foregoing  orders  of  the  Ascomycetes,  and  probably  should  be 
grouped  with  them.  They  are  all  parasitic  in  habit,  and  the 
vegetative  portions  of  the  plant-body  are  greatly  reduced, 
leaving  but  little  more  than  the  organs  of  reproduction. 
Their  life-history  is  but  imperfectly  known,  and  nothing  is 
yet  known  as  to  their  sexual  organs.  They  are  generally 
polymorphic — that  is,  they  assume,  in  their  production  of 
various  kinds  of  spores,  such  apparently  distinct  forms,  that 
these  have  frequently  been  mistaken  for  distinct  plants. 

404. — So  far  as  made  out,  the  life-history  of  the  Uredinege 
appears  to  be  about  as  follows  :  In  the  spring  there  appear  in 
the  tissues  of  the  leaves  of  various  plants  dense  masses  of 


UREDINE^J.  311 

hyphae,  which  penetrate  between  the  cells,  causing  the  leaves 
to  become  usually  much  thickened  and  distorted  in  those 
parts  which  are  infested  with  the  parasitic  growths.  Oc- 


Fig.  216.— Several  stages  of  Puccinia  yramlnis.  A,  part  of  a  vertical  section  of  a 
leaf  of  the  Barberry  (Berberis  vulgarix),  with  a  young  unopened  .widium  fruit ;  '/. 
epidermis.  /.,  section  of  a  Barberry  leaf,  natural  thickness  at  X,  greatly  thickened 
from  A  toward  y ;  it,  epidermis  of  the  under  surface  ;  o,  of  the  upper  "surface  ;  p, 
unopened  tecidinm  fruit ;  a,  a,  a,  opened  Kcidimu  fruits  ;  sp,  sp,  spermagonia.  II., 
a  mass  of  teleutospores  on  a  leaf  of  Couch-grass*  ( Triticum  repens) ;  e,  tlie  ruptured 
epidermis  ;  6.  sub-epidermal  fibres  ol  the  grass  leaf.  ///.,  three  uredospores,  ur, 
with  one  teleutosporu,  t;  sh.  aub  hymenial  hyphaa.  All  highly  m  tgnifled.— ^4  and  /. 
after  Sachs  ;  II.  and  ///.  after  Be  Bary. 

casionally  these  hyphae  are  found  in  other  parenchymatous 
parts  besides  the  leaves,  as  the  petioles,  young  stems,  and 
even  the  flowers  and  fruits.  After  a  short  time  there  form 


312  BOTANY. 

globular  masses,  which  lie  in  the  parenchyma  just  beneath 
the  epidermis  ;  these  are  composed  at  the  bottom  of  an  hyme- 
nium-like  layer  of  sterigmata  (shown  in  Fig.  216,  A  and  /,  as 
a  layer  of  elongated  cells).  Each  sterigma  produces  a  chain 
of  cells,  which  are  at  first  many-sided  from  mutual  pressure, 
but  afterward  spherical.  By  their  growth  these  globular 
masses  finally  burst  through  the  epidermis  (Fig.  216,  L,p), 
and  soon  afterward,  by  the  rupture  of  the  thin  investing 
layer  of  cells  (peridium),  they  become  opened  and  cup- 
shaped  (Fig.  216,  /.,  a,  a,  a).  The  now  rounded  cells  are  set 
free  as  large  yellow  conidia  (or  secidiospores).  At  one  time 
this  stage  was  supposed  to  constitute  a  distinct  plant,  and  it 
received  the  generic  name  of  ^cidium,  hence  it  is  still 
known  as  the  ascidium  stage. 

In  many  (if  not  all)  cases  there  is  a  second  kind  of  repro- 
ductive organ  present,  resembling  in  some  respects  the  aecid- 
ium  fruits  just  described.  These  are  smaller  flask-shaped 
cavities,  which  are  filled  with  slender  hair-like  filaments  (Fig. 
216,  I.,  sp,  sp) ;  these  are  the  spermagonia,  and  they  pro- 
duce, by  the  breaking  up  of  the  filaments,  numerous  ex- 
ceedingly small  oblong  bodies,  the  spermatia.  The  function 
of  these  is  not  known  ;  at  one  time  it  was  supposed  that  they 
were  the  male  reproductive  bodies,  but  it  is  very  doubtful 
whether  they  are  of  this  nature. 

405. — The  conidia  (aecidiospores),  when  they  fall  itpon  the 
leaves  of  the  proper  host  plant,  germinate,  and  penetrate 
thestomata,  thus  reaching  the  leaf  parenchyma,  where  a  dense 
mycelium  is  formed.  Upon  this  are  formed,  within  a  short 
time,  stalked  spores  (uredospores,  Fig.  216,  ///.,  ur)  ;  these 
finally  burst  through  the  epidermis,  and  form  orange-colored 
spots  upon  the  leaves.  The  uredospores  fall  off  very  easily, 
and  germinate  quickly,  giving  rise  immediately  to  another 
mycelium  (Fig.  217,  D),  which  produces  uredospores,  Avhich 
may,  in  turn,  give  rise  to  new  mycelium,  and  so  on  indefi- 
nitely. The  function  of  the  uredospores  is  clearly  the  quick 
reproduction  of  the  fungus. 

406. — After  the  production  of  uredospores  has  continued 
for  some  time,  the  same  mycelium  gives  rise  to  stalked,  thick- 


UREDINE^E.  313 

walled  bodies  (teleutospores,*  or  pseudo-spores),  which  are 
one,  two,  three,  or  many-celled  (Fig.  210,  ///.,  t).  Like 
the  uredospores,  the  teleutospores  are  produced  beneath  the 


.  217.— Pucclnla  graminis.  A,  germinating  teleutospore,  t,  with  promycelium 
forming  the  sporidia,  sp.  B,  similar  promycelium,  with  spondia.  C,  a  sporidium, 
»1>,  germinating  on  a  piece  of  the  under  side  of  a  leaf  of  the  Barberry,  the  mycelium, 
£  penetrating  the  epidermis.  Z>,  a  (Terminating  uredospore,  u,  fourteen  hours  after 
being  placed  on  the  leaf  of  a  grass,  forming  a  branched  mycelium.  Highly  magnified. 
—After  Be"  Bary. 

epidermis  of  their  hosts,  which   in  their  growth  they  burst 
through,  and  appear  as  small  rounded  clusters  (sori),  or  more 

*  From  the  Greek  reAevrr),  end  ;  so  named  because  it  is  generally  the 
last  reproductive  body  of  these  fungi  produced  in  the  season. 


314 


BOTANY. 


or  less  elongated  lines.  In  color  they  are  almost  invariably 
brown  or  nearly  black,in  marked  contrast  to  the  reddish  yellow 
(orange)  uredospores.  In  some  cases  they  are  produced  early 
in  the  season,  but  in  the  greater  number  of  cases  they  appear 
in  the  autumn,  and  then  remain  through  the  winter  upon 
the  dead  stems  of  their  host  plants.  The  following  spring 
the  teleutospores  germinate  by  sending  out  a  jointed  filament 
(the  promycelium)  from  each  cell ;  this  grows  to  several  times 
the  length  of  the  teleutospore,  and  then  sends  out  a  few  lateral 
branches,  each  of  which  bears  a  small  terminal  cell,  a  sporid- 
ium  (Fig.  217,  A  and  B,  and  Fig.  218).  The  sporidia  are 
extremely  minute,  and,  as  a 
consequence,  are  carried  about 
from  place  to  place  in  the  wind 
with  great  ease.  When  they 
fall  upon  the  proper  plant,  each 
sporidium  sends  out  a  minute 
filament,  which  perforates  the 
epidermis-cells,  and  from  these 
passes  into  the  leaf  parenchy- 
ma, where  it  develops  into  a 
mycelium  (Fig.  217,  C).  From 
this  last  mycelium  the  aecidium 
fruits  first  described  develop. 

Fig.  218. — Germinating  teleutocpore 

of  tfwtinia  Molinut,  showing  promy-  (a)  The  life-cycle,  as  above  given, 
celium  and  sporidia. -After  Tulasne.  J8  apparently  abridged  in  some  of 
the  Uredineae.  The  secidium  and  uredo  stages  are  merged  into  one,  or 
either  the  first  or  second  is  entirely  wanting.  This  appears  to  be  the 
case  in  Phragmidium,  Gymnoaporangium,  Melampsora,  etc. 

(6)  With  most  of  the  species  it  happens  that  the  secidiospores  (conidia) 
develop  upon  one  host,  and  the  uredospores  and  teleutospores  upon  an- 
other. This  alteruation,  which  is  termed  by  De  Bary  hetercecism,  has 
added  very  much  to  the  difficulty  of  the  study  of  these  fungi,  and  pos- 
sibly the  apparent  abridgement  of  the  life-cycle  above  mentioned  may 
in  some  instances  be  only  an  obscure  hetenBcisin. 

(c)  Thus  far  the  sexual  organs  have  not  been  discovered  ;  Sachs* 
argues  that  they  must  precede  the  secidiospores,  and  that  the  secidium 
fruit  is  in  all  probability  the  result  of  a  sexual  act.  He  bases  his  argu- 
ment upon  the  law  that  the  reproductive  organs  of  most  complex  struc- 

*  •  Lehrbnch  der  Botanik,"  4te  Auflage,  1874,  p.  331. 


URKD1NEJE. 


315 


ture  follow  or  proceed  from  a  sexual  act  ;  and  maintains  that  the  aecid- 
ium  fruit  is  more  complex  in  structure  than  any  of  the  others.  He 
further  says,  "  The  secidium  fruit  corresponds,  then,  to  the  perithecium  of 
the  Ascomycetes,  the  secidiospores  to  the  ascospores  ;  and  the  uredo- 
spores  and  teleutospores  are  evidently  differ- 
ent forms  of  conidia."  It  is  very  doubtful, 
however,  whether  future  investigations  will 
prove  the  correctness  of  Sachs'  surmise.  It  is 
much  more  probable  that  the  teleutospores  re- 
sult from  a  sexual  act,  and  that  they  are  to 
be  compared  to  the  asci  of  the  Ascomycetes. 
The  teleutospores  are  possibly  reduced  asci, 
containing  one  or  more  large  ascospores ;  in 
some  canes-^.,  in  Puccinia  HOtoMi—n 
outer  investing  membrane  can  be  distinguish- 
ed  after  treatment  with  potassic  hydrate, 
while  in  Puccinia  ( Uropyxis)  Amorphce  there  of  the  mature  teleutospore. 
is  "a  deciduous  outer  coat,"*  which  contains  Highly  magnified, 
the  double  spore,  and  (when  moistened)  a  mass  of  jelly.  In  both  these 
cases  the  membranous  covering  closely  resembles  an  ascus  which  fits 
closely  over  its  contained  double  spore.  In  the  genus  Phragmidium 
(Fig.  220),  especially  in  young  teleutospores,  the  resemblance  to  asci 
and  ascospores  is  still  more  striking  ;  the  so- 
called  "  cells"  of  the  teleutospore  originate  as  so 
many  separate  masses  in  the  interior  of  a  large 
ascus-lrke  membrane  (Fig  219) ;  in  their  further 
development  the  cells  become  large,  and  at  last 
fill  up  the  whole  cavity,  and  then  have  the  ap- 
pearance of  Fig.  220. 

The  resemblance  of  the  teleutospores  to  re- 
duced asci  is  close  enough  to  make  it  probable 
that  sexual  organs  resembling  those  of  Asco- 
mycetes will  be  found  to  precede  them.  This 
is  rendered  the  more  probable  from  the  resem- 
blance of  secidiospores,  spermatia,  and  uredo- 
spores  to  the  conidia,  spermatia,  and  stylospores 
of  various  Ascomycetous  funjri.f 

(d)  The  principal   genera   in  this  order  are 
Uromyces  and  Melampsora  with  one-celled  te- 
leutospores, Puccinia   and  Gyimiosporangium, 
with  two  cells,  and  Phragmidium  (Fig.  220)  with 
many  cells.    Many  species  are  known,  there  being  in  the  genus  Puc- 


Fig.  220  -Mature  teleu- 
tospores or  Phragmidium 
bulbosum.  Highly  magni- 
fied.-After  Cooke. 


*  So  described  by  Berkeley  :  "  Introduction  to  Cryptogamic  Botany," 
1857,  p.  325. 
f  Some  of  these  resemblances  were  pointed  out  many  years  ago  by 


316  BOTANY. 

cinia  alone  from  forty  to  fifty  species  in  the  United  States.  They  at- 
tack many  species  of  Phanerogams,  but  are  scarcely  known  as  para- 
sites upon  Cryptogams.  The  first  stage  was  long  known  as  the  genus 
jfflcidium,  and  under  this  many  supposed  species  were  described,  and 
this  is  still  the  case  in  all  English  systematic  works  ;  in  the  same  way 
the  second  stage  gave  rise  to  the  supposed  genera,  Uredo,  Trichobasia, 
etc.,  and  even  these  are,  to  a  great  extent,  retained  in  the  ordinary 
books,  although  their  autonomy  was  long  since  disproved. 

(e)  One  of  the  best  known  species  of  this  order  is  that  which  appears 
upon  wheat,  oats,  and  some  other  cultivated  grasses,  producing,  or 
rather  being,  the  disease  known  as  Rust  (Puccinia  graminis).  It  ap- 
pears in  the  spring  upon  the  leaves  of  the  Barberry,  developing  there 
the  secidiospores  (conidia),  and  constituting  what  for  a  long  time  has 
been  known  as  the  Barberry  Cluster-Cups,  or  Barberry  Rust  (Fig.  216, 
A  and  /.).  Later  in  the  season,  and  usually  after  the  Cluster-Cups 
have  entirely  disappeared  from  the  Barberry,  the  uredo  stage  begins 
to  make  its  appearance,  first,  upon  the  leaves,  and  then  upon  the  stems 
of  the  wheat,  oats,  etc. ;  at  first  it  may  be  detected  by  the  pale  yellow- 
ish or  whitish  spots  on  the  leaves  ;  these  mark  the  places  where  the 
uredos;  ores  are  b<  ginning  to  form  beneath  the  epidermis.  Within  a 
few  days  the  uredospores  (Fig.  21G,  ///. ,  ur)  break  through  the  epider- 
mis and  expose  long  lines  of  the  orange-red  spores.  By  the  quick  ger- 
mination of  the  uredospores,  first  produced,  the  fungus  is  greatly 
ir  creased,  so  that  frequently  the  host  plant  is  destroyed  before  reach- 
ing its  maturity.  This  stage  is  known  popularly  as  the  Red  Rust  of 
wheat,  oats,  barley,  11  nd  other  similar  grasses.  Still  later  in  the  season, 
and  usually  after  the  ripening  of  the  host  plants,  the  dark-colored 
teleutospores  (Fig.  216,  //.)  appear  in  long  black  lines,  sometimes  upon 
the  leaves,  but  more  frequently  upon  the  stems,  and  in  ordinary 
cases  upon  the  uncut  part  of  the  stem,  viz.,  the  "  stubble."  This  stage 
Is  known  as  the  Black  Rust.  The  teleutospores  remain  upon  the  dead 
stems  through  the  winter,  and  in  the  following  spring  germinate  and 
produce  sporidia,  which  give  rise  to  a  mycelium  in  the  Barberry 
leaves  (Fig.  217,  A,  B,  and  C). 

De  Bary.f  by  placing  the  teleutospores  upon  young  leaves  of  the 
Barberry,  succeeded  in  producing  the  secidium  stage,  thus  proving' 
Barberry  rust  to  be  but  a  stage  of  Puccinia  r/raminis.  Similarly  it 
has  been  shown  that  the  secidiospores  of  Barberry  rust  will  not  grow 
upon  Barberry  leaves,  but  that  when  placed  on  a  leaf  of  wheat,  oats, 

Frederick  Currey.  In  a  paper  "  On  the  Affinities  of  the  Uredineae,"  pre- 
sented to  the  Iowa  Academy  of  Sciences,  May,  1878,  I  pointed  out  that 
the  structural  similarity  of  Uiedinea;  and  Ascomycetes  rendered  it 
probable  that  the  sexual  organs  of  the  former  preceded  the  teleuto- 
apores.  I  did  not  then  know  of  Carrey's  paper, 
t  Published  in  Monattber.  d.  Berl.  Acnd.,  1865. 


USTILAGINE^E.  317 

barley,  etc.,  they  send  out  filaments,  whcih  pass  through  the  stomata, 
and  give  rise  to  a  mycelium,  which,  in  about  a  week,  produces  uredo- 
spores. 

(/)  Uredinese  are  easily  obtained  for  study  in  either  the  first,  second, 
or  third  stage.  In  most  species  the  aecidium  stage  occurs  in  spring  or 
early  summer,  the  second  in  spring  or  summer,  and  the  third  in  the 
autumn  ;  in  some  species,  however,  the  teleutospores  are  produced  in 
the  spring,  as  in  Oymnosporangium  and  Puccinia  Anemones. 

(g)  The  sporidia  may  be  obtained  by  placing  pieces  of  grass  stems 
containing  teleutospores  in  a  damp  atmosphere,  after  soaking  for  a  few 
hours  in  water.  The  teleutospores  should  be  freshly  taken  in  most 
caseg  from  those  which  have  remained  upon  the  stems  out-of-doors 
during  the  winter. 

407.— Order  Ustilaginese.  The  plants  which  compose 
this  order  are  all  parasites  living  in  the  tissues  of  Phanero- 
gams. Like  the  Uredineae,  the  Ustilaginea3  send  their  my- 
celium through  the  tissues  of  their  hosts,  and  afterward 
produce  spores  in  great  abundance,  which  burst  through  the 
epidermis.  There  is,  however,  in  many  respects  a  greater 
simplicity  of  structure  in  the  plants  of  the  present  order 
than  in  the  Uredineae,  and  this  has  induced  some  botanists 
to  doubt  their  relationship  to  the  last-named  order  ;  how- 
ever, it  appears  that  the  simplicity  is  one  due  rather  to 
degradation  than  to  any  essential  difference  in  structural 
plan. 

408. — The  mycelium  of  the  Ustilagineae  is  well  defined, 
and  consists  of  thick-walled,  jointed,  and  branching  hyphge, 
which  are  generally  of  very  irregular  shape.*  The  hyphaa 
grow  in  the  intercellular  spaces,  as  well  as  within  the  cell 
cavities  of  their  hosts.  They  send  out  suckers  (haustorid), 
which  penetrate  the  adjacent  cells  much  as  in  the  Perono- 
sporeae  ;  these  are  more  abundant  in  the  compact  tissue  of 
the  nodes  of  stems  than  in  the  long-celled  tissue  of  the  in- 
tcrnodes.  The  mycelium  generally  begins  its  growth  when 
the  host  plant  is  quite  young,  and  grows  with  it,  spreading 
into  its  branches  as  they  form,  until  it  reaches  the  place 
of  spore-formation.  In  perennial  plants  the  mycelium  is 

*  The  following  account  of  the  Ustilaginese  is  based  upon  an  article  on 
this  order  by  Dr.  A.  Fischer  von  Waldheim,  published  in  Pringsheim's 
"Jahrbiicher  fur  Wissen.  Bot.,"  1869.  A  translation  appeared  in  the 
Transactions  of  the  N.  T.  State  Agricultural  Society,  1870. 


318  BOTANY. 

perennial,  the  fungus  reappearing  year  after  year  upon  the 
same  stems,  or  upon  the  new  stems  grown  from  the  same 
roots ;  in  annuals  it  must  obtain  a  foothold  in  the  young 
plants  as  they  grow  in  the  spring. 

409. — The  mycelium  can  be  traced  in  the  Monocotyle- 
dons often  for  long  distances  ;  thus  in  the  smut  of  Indian  corn 
( Ustilago  Maydis},  at  the  time  the  spores  are  found  in  the 
distorted  grains  the  hyphae  have  been  detected  at  all  inter- 
mediate points  down  to  the  lower  iuteruodes,  and  in  the 
smut  on  wheat  ( Ustilago  carbo)  they  have  been  observed  in 
every  part  of  the  plant,  from  the  root  through  the  stem  to 
the  inflorescence.  In  neither  case,  however,  are  the  hyphge 
to  be  found  in  parts  through  which  it  is  not  necessary  for 
them  to  pass  in  order  to  reach  the  point  where  the  spores 
are  formed  ;  thus  they  are  usually  not  found  in  the  leaves 
unless  spores  are  formed  in  them. 

410. — The  formation  of  spores  appears  to  have  some  re- 
lation to  the  development  of  the  host  plant,  as  they  form 
only  in  certain  parts  of  the  latter,  and  are  not  produced 
until  the  growth  of  these  parts  has  taken  place.  Thus  in 
the  Bunt  of  wheat  (Tilletia  caries)  the  spores  are  formed 
only  in  the  young  ovaries ;  in  the  anther  smut  of  the  Si- 
lenecB  ( Ustilago  antJierarum)  the  spores  are  formed  in  the 
young  anthers  ;  in  one  of  the  smuts  of  the  sedges  ( Ustilago 
urceolorum)  they  form  on  the  upper  surface  of  the  ovary,  and 
in  the  smut  of  wheat,  oats,  etc.,  in  the  young  flowers.  In 
cases  like  these  it  is  evident  that  the  time  of  spore-forma- 
tion is  dependent  upon  the  development  of  the  flowers  of 
their  host ;  and  if  these  are  earlier  or  later  in  their  appear- 
ance, the  spore-formation  will  vary  accordingly.  In  the 
smut  of  Indian  corn  (Ustilago  Maydis),  on  the  other  hand. 
the  spore-formation  may  take  place  in  other  parts  of  the 
plant,  as  well  as  in  the  ovary  ;  thus  it  not  infrequently  makes 
its  appearance  upon  the  stems,  and  even  upon  the  leaves.  In 
Ustilago  hypogcea  the  spores  are  produced  underground 
upon  the  root  of  the  host  plant  (Linaria  spuria),  and  in 
Ustilago  marina,  in  the  tissues  of  Scirpus  parvulus,  under 
water  ;  with  these  two  exceptions,  the  spore-formation  always 
takes  place  in  parts  above  ground. 


USTILAGINE^.  319 

411. — Immediately  preceding  the  formation  of  spores 
the  hyphae  give  rise  to  many  branches,  which  differ  much  in 
appearance  from  the  ordinary  ones.  This  takes  place  in 
those  parts  of  the  host  plant  where  the  spores  are  afterward 
produced.  These  spore-forming  hyphae  are  thicker  than  the 
vegetative  ones,  and  are  more  gelatinous ;  they  are  more  or 
less  granular,  and  they  sometimes  contain  oil  globules. 

412. — The  spores  are  formed  in  Tilletia  caries  by  little 
lateral  branches  budding  out  upon  the  spore-forming  hyphae, 
and  acquiring  a  pear-shaped  outline  ;  they  become  thicker 
and  more  spherical,  and  each  eventually  secretes  a  dark,  thick 
wall  (Fig.  224,  k'  and  k).  When  mature,  the  spores  become 
free  by  the  drying  up  of  the  attaching  pedicel.  In  Ustilago 
the  spore-forming  hyphae  break  up  their  contents  into 
spores,  and  in  some  cases — as,  for  example,  in  Ustilago 
Maydis — the  process  much  resembles  the  formation  of  asco- 
spores  in  asci  (Fig.  221).  It  frequently  happens  that  the 
spore-forming  hyphae  fuse  together  on  account  of  the  gelat- 
inous nature  of  their  envelopes  ;  when  this  takes  place,  the 
spores  are  formed  in  very  irregular  masses  (Fig.  222,  b). 

In  Sorisporium  Saponarm  this  fusing  takes  place  to  so 
great  an  extent  that  the  real  nature  of  the  process  is  greatly 
obscured.  The  spore-forming  hyphae,  which  are  very  abun- 
dant, become  curved  at  their  extremities,  and  many  of  these 
twist  themselves  into  a  little  ball,  and  are  fused  into  a  single 
gelatinous  body,  which  eventually  becomes  a  mass  of  spores. 
The  real  nature  of  the  spore-formation  is  probably  indicated 
by  the  "solitary  spores,"  which  appear  singly  upon  those 
spore-forming  hyphae  which  do  not  compact  themselves  into 
balls  ;  in  these,  the  resemblance  to  asci  containing  single 
ascospores  is  striking  (Fig.  223). 

413. — The  spores,  when  ripe,  have  a  double  wall.  The 
outer — the  epispore — is  thick,  usually  brown  or  black,  some- 
times smooth,  but  frequently  more  or  less  rough  by  projec- 
tions,-or  marked  by  reticulations  (Fig.  224,  e).  The  inner 
wall — the  endospore — is  a  delicate  colorless  membrane,  which 
protrudes  through  the  ruptured  epispore  in  germination. 

414. — The  germination  of  the  spores  has  been  made  out 


320 


BOTANY. 


for  a  few  species  only.  *  In  all  which  have  been  examined 
the  spore  sends  out  apromycelium,  which  is  generally  short 
and  jointed,  and  upon  this  several  sporidia  are  produced, 
much  as  in  the  Uredineae.  In  Tilletia  caries  the  promyce- 
lium  produces  a  tuft  of  slender  branches  (Fig.  224,  h),  which 


FIG.  222. 


Flo.  223. 


Fig.  221. — Spore-formation  in  Ustilago  Maydte.  a,  the  end  of  a  spore- forming  hy- 
pha containing  n  row  of  young  spores  ;  b,  another  spore-forming  hypha,  containing 
two  young  spores;  c,  a  spore  nearly  ripe,  still  surrounded  by  the  gelatinous  mem- 
brane of  the  hypha.  X  1800.— After  Fischer  von  Waldheim. 

Fig.  222.-  Snoie-formaiion  in  U#tilar/o  anf/ierarum.  a.  an  isolated  gelatinous  hy- 
pha, with  the'conteuts  distinctly  breaking  up— at  the  lower  end  a  portion  not  yet 
broken  up  ;  b,  annmber  of  gelatinous  hyphte  fused  into  an  irregular  mass,  showing 
the  formation  of  nv>ny  spores  ;  c,  a  spore  nearly  ripe,  still  surrounded  by  the  gelat- 
inous hypha  membrane,  also  a  voting  cpore  upon  a  lateral  branch,  a  and  c  x  1800  ; 
b  X  900  —After  Fischer  von  Waldheim. 

Fig.  223. — Formation  of  "solitary  spores"  in  Sorispoi  turn  Saponarite.  a,  hyphm 
with  two  young  spores;  6,  aspoie  at  a  later  stage;  c,  hyphre  with  spores  in  differ- 
ent stages  of  development;  at  c' a  thin  wall  has  formed  around  the  contained  pro- 
toplasm as  in  b  ;  at  c"  the  wall  is  much  thicker,  and  at  c'"  it  is  still  thicker.  X  300.— 
After  De  Bary. 

have  been  seen  to  unite  laterally  by  a  kind  of  conjugation 
(not,  however,  of  a  sexual  nature,  in  all  probability)  ;  from 
these  branches  (called  by  some  writers  "  secondary  spores  ")f 

*  According  to  Fischer  von  Waldheim,  the  germination  of  the  fol- 
lowing species  is  known,  viz.,  Tilletia  caries,  T.  Lolif,  Ustilago  an- 
t/terarum,  V.  flnxculorum,  U.  carbo,  U.  destruens,  U.  Maydis,  U.  recep- 
taculorum,  U.  longixsima,  U.  Vaittantii,  Urocystis  pompholygode*, 
Uroc.  occulta. 

f  De  Bary  calls  these  branches  sporidia,  and  what  are  here  called 
.«!>< iriilia,  he  calls  secondary  sjwridia. 


USTILAGINE^E. 


321 


there  grow  out  small  sporidia,  which  germinate  by  sending 
out  a  slender  hypha ;  when  this  hypha  conies  in  contact 
with  the  proper  host  plant,  it  penetrates  the  walls  of  its 


Fi^.  %M.—  TiUetia  caries,    d,  tra  sverse  section  of  an  infected  wheat-grain  ;  «,  ripe 
spore  :  /.  the  firrt  stage  of  germin  tion  :  fir,  the  formation  of  a  branching 
Iron,  with  granular  protoplasm    u  its  upper  end;    A,   the  formation  < 
l>rauche^  which  unite  by  a  kind  of  conjugation  ;  the  ends  of  these  branches  give  rise 
somewhat  later  to  very  small  spo  '" 
phie  a>-e  produced,  which  peueira 


promyce- 
of  Blender 


id  when  thet-e  germinate  very  slendtr  hy- 
epidermis  as  at  i  ;  £',  mycelium  from  the 


young  ovary  of  the  wheat — two  small  lateral  branches  are  shown,  from  which  spores 
will  develop  ;  k,  spores  more  fully  developed.— d,  after  (Ersted  ;  e-h,  after  Tulasne, 
X  460  ;  i-*,  after  Kuhn,  X  300. 

cells,  and  thus  gains  admittance  to  its  interior,  where  it  pro- 
duces a  new  mycelium*  (Fig.  224,  i).  In  Ustilago  carbo  the 

*  This  is  upon  the  authority  of  Kuhn  :  "  Krankheiten  der  Culturjre- 
wacbae,"  1859.  There  are  some  doubts  as  to  the  correctness  of  his 
observations,  and  they  have  not  bet-n  confirmed  bv  any  one, 


322  BOTANJ. 

promycelium  branches  less  frequently,  and  generally  pro- 
duces from  three  to  four  sporidia.  In  no  other  case  than 
Tilletia  caries  is  the  mode  of  entrance  of  the  fungus  into 
the  host  plant  known. 

415. — No  sexual  organs  have  yet  been  discovered.  They 
are  probably  to  be  looked  for  just  preceding  the  formation 
of  the  spore-bearing  hyphae.  The  uniting  of  the  hypha- 
branches  in  the  germination  of  the  spores  of  Tilletia  cari*.'.-- 
(Fig.  224,  h)  has  probably  no  sexual  significance. 

(a)  In  the  study  of  the  mycelium  of  the  Ustilaginese,  the  hyphae 
may  be  made  more  distinct  in  thin  sections  of  the  host  plant  by  the 
application  of  a  solution  of  potassic  hydrate.     A  similar  effect  is  pro- 
duced by  treating  the  specimen  for  some  hours  with  thinned  glycerine. 

(b)  In  the  study  of  the  spore  development,  the  specimens  must  be 
examined  in  very  early  stages  of  the  growth  of  the  fungus.     This  can 
generally  be  done  in  the  case  of  those  species  which  affect  the  Gram- 
ineae,  by  taking  the  affected  "  suckers  "  or  lateral  branches  of  the  host 
plant,  after  the  spores  are  pretty  well  advanced  on  the  main  stem. 

(c)  Upon  the  application  of  a  solution  of  iodine,  the  contents  of  the 
young  spores  become  yellow,  indicating  their   protoplasmic   nature  ; 
treated  with  Schultz's  solution,  the  contents  become  brownish  yellow. 
The  gelatinous  membrane  is  not  colored  by  the  last-named  reagent, 
showing  that  it  is  not  cellulose  ;  but  when  treated  with  a  solution  of 
potassic  hydrate,  it  is  colored  yellow,  and  in  sulphuric  acid  it  is  dis- 
solved. 

(d)  The  ripe  spores  frequently  require  to  be  treated  with  reagents  to 
bring  out  their  structure.     The  endospore  may  be  rendered  visible  by 
the  application  of  sulphuric  acid  which   makes   the   epispore   more 
transparent  ;  in  concentrated  sulphuric  acid  the  structure  of  the  epi- 
spore  is  made  much  plainer;  treatment  with  a  solution  of  potassic 
hydrate  causes  the  spore  to  swell  up. 

(e)  In  the  study  of  the  germination  of  the  spores,  it  is  only  neces- 
sary to  place  freshly  gathered   spores  in  a  drop  of  water,  or  upon 
moistened  earth,  or  in  an  atmosphere  kept  moist,  as  under  a  bell-jar. 
Germination  takes  place  in  the  proper  temperature  (20°  to  25°  C.,or  68 
to  77°  Fahr.)  in  from  three  hours  (UstUago  longissima)  to  fifty  or  sixty 
(Tilletia  caries). 

(/)  All  attempts  thus  far  to  determine  experimentally  the  mode  of 
entrance  of  the  fungus  into  the  tissues  of  the  host  plant  have  failed, 
with  the  exception  of  Kuhn's  experiments  upon  Tilletia  caries.  The 
recent  attempts  made  by  Fischer  von  Waldheim  upon  Ustilago  carbo 
and  other  species,  although  made  seemingly  under  the  most  favorable 
conditions,  utterly  failed.  He  placed  fresh  spores  upon  the  germinated 
seeds  of  oats  and  barley,  upon  the  entire  surface  of  the  rootlets,  and 


BASIDIOMYCETES.  323 

also  upon  all  parts  of  the  young  stems  and  leaves.  He  even  sprinkled 
the  young  plants  with  germinated  spores,  and  in  one  series  of  experi- 
ments brought  the  young  rootlets  in  contact  with  the  promycelium 
and  sporidia  of  the  germinating  spores.  In  no  case,  however,  was 
there  any  penetration  of  the  fungus  into  the  host  plant. 

(g)  The  most  important  genus  of  the  order  is  Ustilago,  which  con- 
tains many  species,  the  most  common  of  which  are  U.  carbo,  the 
gmut  of  wheat,  oats,  barley,  and  many  other  grasses  ;  U.  Maydis,  the 
smut  of  Indian  corn  ;  U.  de*truens,  on  Setaria  glauca;  U.  utriculosa, 
on  species  of  Polygonum ;  IT.  itrceolorum,  on  many  species  of  Carex. 
Tilletia  contains  several  species,  but  one  of  which — T.  caries — has  yet 
been  detected  in  this  country.  Of  Urocystis  we  have  several  species,  of 
which  U.  cepulce,  on  onions,  and  U.  pompholygodes,  on  Ranunculacese, 
are  best  known. 

§  IV.    CLASS  BASIDIOMYCETES. 

416. — The  plants  of  this  class  are  among  the  largest  and 
finest  of  the  fungi.  They  are  mostly  saprophytes,  provided 
with  an  abundant  mycelium,  which  ramifies  through  the 
nourishing  substratum,  and  from  which  there  arises  after- 
ward a  spore-bearing  growth,  the  sporocarp.  The  spores,  of 
which  but  one  kind  is  yet  certainly  known,*  are  produced 
upon  slender  outgrowths  from  the  ends  of  enlarged  cells, 
termed  basidia.  The  basidia  are  usually  so  arranged  as  to 
form  an  hymenium,  which  is  at  length  external  in  Hymeno- 
mycetes,  and  internal  in  most  Gasteromycetes. 

417. — The  sexual  organs  probably  precede  the  formation 
of  the  sporocarp,  but  they  have  been  but  little  studied. 
(Ersted  discovered!  bodies  in  Agaricus  variabilis  which, 
judging  from  his  description,  bear  a  considerable  resemblance 
to  the  sexual  organs  of  Peziza.  Whether  they  occur  through- 
out the  class  is  at  present  entirely  unknown,  and  as  (Er- 
sted's  discovery  has  not  been  confirmed  by  other  observers, 
the  whole  question  as  to  the  sexual  organs  of  the  Basidiomy- 

*  (Ersted,  in  "  Kongeliire  Danske  Videnskabernes  Selskabs  Forhand- 
linger,"  Copenhagen,  1865  (translated  in  Qr.  Jour.  Mic.  Science,  1868,  p. 
18),  describes  certain  little  stalked  bodies  which  he  found  growing  upon 
the  mycelium  of  Agaricus  variabilis,  and  which  he  regards  as  conidial 
in  their  nature.  Spermatia  also  occur  on  the  Tremellini. 

f  Described  in  bis  paper  just  referred  to  above. 


324  BOTANY. 

cetes  must  be  considered  as  involved  in  much  doubt.  Two 
orders  may  be  readily  separated  in  this  class,  the  Gasteromy- 
cetes  and  the  Hymenomycetes. 

418.— Order  Gasteromy cetes.  The  plants  of  this  order 
are  saprophytes,  producing  sporocarps  which  are  often  of 
large  size,  and  usually  of  a  more  or  less  globular  outline, 
sometimes  long-stalked.  The  spores  are  always  borne  in  the 
interior  of  more  or  less  regular  cavities,  and  from  these  they 
escape  by  the  drying  and  rupture  of  the  surrounding  tissues. 
419.  — The  mycelium  of  the  Gasteromycetes  penetrates  the 
substance  of  decaying  wood,  and  the  soil  filled  with  decaying 
organic  matter.  It  is  composed  of  colorless  jointed  hypha?, 
which  usually  aggregate  themselves  into  cylindrical  root- 
like  masses.  After  an  extended  vegetative  period,  the  my- 
celium forma  upon  its  root-like  portions  small  rounded 
bodies,  the  young  sporocarps,  which  increase  rapidly  in  size, 
and  assume  the  form  characteristic  of  the  different  genera. 

420. — The  sporocarps  are  composed  of  hyphae  which  are 
much  interlaced  ;  in  the  interior  they  are  more  loosely  ar- 
ranged, while  externally  they  form  a  more  or  less  well-defined 
limitary  tissue,  the  peridium.  In  some  genera  the  peridium 
is  composed  of  two  or  more  layers,  as  in  the  Earth-star  ( U wit- 
ter). The  spores  are  borne  upon  hymenial  layers  which  line 
cavities  in  the  interior  of  the  sporocarp.  The  basidia  upon 
which  the  spores  are  borne  are  the  rounded  or  elongated  ter- 
minal cells  of  hypha-branches  ;  each  basidium  bears  four  or 
more  (frequently  eight)  spores  upon  the  ends  of  as  man} 
small  projections  (spicules).  In  Phallus  and  its  allies  the 
hymenial  cavity  lies  beneath  the  double  peridium  and  paral- 
lel to  its  surface  ;  when  the  spores  are  formed,  by  the  rapid 
growth  of  the  axial  portion  of  the  sporocarp,  the  hymen  him 
is  carried  up  through  a  rent  in  the  apex  of  the  peridium  and 
the  spores  thus  set  free.  In  the  Earth-star  (Geaster),  Puff- 
ball  (Ly  coper  don),  and  their  allies,  the  hymenial  cavities  are 
numerous,  of  irregular  shape,  and  scattered  through  the  tis- 
sue of  the  sporocarp.  The  spores  are  set  free  by  the  rupture 
of  the  peridium,  and  the  drying  of  the  whole  sporocarp, 
thus  reducing  its  interior  hyphae  to  a  fine  powder.  In  the 
Puff-ball  the  single  peridium  ruptures  irregularly,  but  in  the 


GASTEROMYCETES.  325 

Earth-star  the  outer  peridium,  which  is  dense,  and  when  dry 
quite  hard,  splits  from  the  top  into  partially  separated  seg- 
ments, which  recurve  and  expose  the  inner  more  delicate  perid- 
ium ;  the  latter  ruptures  more  or  less  regularly  at  the  top,  and 
thus  allows  the  escape  of  the  spores  and  dusty  broken-up 
hyphae. 

421. — In  the  curious  little  Crucibulum  and  its  allies  the 
structure  and  mode  of  development  are  much  more  compli- 
cated. The  mycelium,  which  grows  over  the  surface  of  de- 
caying wood,  forms  first  a  rounded  mass  of  hyphae  in  its 
centre  ;  this  becomes  cylindrical,  and  then  undergoes  several 
remarkable  changes.  In  the  interwoven  hyphae  of  the  inte- 
rior, at  certain  points,  there  is  a  very  great  increase  in  the 
number  of  hyphae  and  the  density  of  the  tissue  ;  this  takes 
place  with  such  regularity  that  several  round  bodies  are 
formed.  The  interior  of  each  of  these  round  bodies  is  at 
first  composed  of  interwoven  hyphae,  but  these  become  mu- 
cilaginous, and  finally  entirely  dissolved,  forming  a  central 
cavity  in  each  mass  ;  into  these  cavities  hypha-branches  now 
grow,  and  line  them  with  an  hymenial  layer  of  spore-bearing 
basidia.  The  round  bodies  are  thus  sporangia.  While  the 
above-described  changes  are  going  on,  the  tissue  lying  between 
the  sporangia  undergoes  conversion  into  mucilage,  and  be- 
comes entirely  dissolved,  leaving  only  a  surrounding  wall 
(the  peridium),  and  slender  pedicels  composed  of  hyphae, 
which  support  the  sporangia.  When  these  changes  are  com- 
pleted, the  peridium  ruptures  at  the  top  and  opens  out, 
forming  a  cup-shaped  receptacle,  in  which  the  sporangia  lie. 
The  sporocarp  of  Crucibulum  is  thus  a  much  more  highly 
developed  organism  than  that  of  Lycoperdon,  although  not 
differing  from  it  in  any  essential  point  of  structure. 

422. — No  sexual  organs  have  yet  been  discovered  in  the 
Gasteromycetes,  but  analogy  points  to  their  probable  exist- 
ence upon  the  mycelium  just  previous  to  the  first  appearance 
of  the  gpore-bearing  portion  of  the  plant  (sporocarp). 

423. — The  mode  of  germination  of  the  spores  is  as  yet 
almost  entirely  unknown. 

(a)  The  principal  genera  of  the  Gasteromycetes  are  Phallus,  which  in- 
cludes the  common  Stink-horn;  Lycoperdon  including  several  species  of 


326 


BOTANY. 


Puff-balls,  of  which  the  best  known  is  L.  giganteum,  the  Giant  Puff- 
ball,  an  edible  species,  from  ten  to  thirty  cm.  in  diameter  ;  Oeaster, 
the  Earth-stars,  including  several  species,  and  Crucibulujn,  of  which  C. 

vulgcvre  is  very  common. 

(6)  This  order  presents 
no  unusual  difficulties  to 
the  student,  and  it  is  one 
which  should  receive  more 
attention  than  it  has  hith- 
erto. For  the  study  of 
the  structure  the  speci- 
mens should  be  taken  in 
their  earlier  stages,  as  but 
little  can  be  made  out 
after  the  hyphse  begin 
breaking  up  or  dissolving. 

424.  —  Order  Hy- 
menomycetes.  These 
plants  are  doubtless  to 
be  regarded  as  the 
highest  of  the  chlo- 
rophyll -  free  Carpo- 
sporeae.  They  are  not 
only  of  considerable 
size  (ranging  from  one 
to  twenty  centimetres, 
or  more,  in  height), 
but  they  present  a 
structural  complexity 
which  is  so  much 
greater  than  that  of 

Fig.  225.— Development  of  Agaricus  campustris.  the   other   Orders,  that 
A,  underground  mycelium  (m),  bearing  numerous     ,  ' 

young  sporocarps  of  various  sizes.  /.,  vertical  sec-  tlieV  Cannot  but  be  T6- 
tionofa  young  eporocarp,  showing  its  attachment  "-,  -,  ,-,  i  •  , 

to  the  mycelium, V  //.,  verticaf  section  of  an  garded  as  the  highest 
older  sporocarp,  showing  the  annular  opening,  1.  »  11  *  -r  -i 

///.,  the  same  at  a  still  later  stage.  IV.,  youngspSro-  Ol    the    Iimgl.         Like 

Be'aarnydmae  the      Guteromycete* 
they  produce  an  abun- 

yonng  sporocarp.  All  natural  size.— After  Sachs.  dailt  mycelium  Under- 
ground, or  in  the  substance  of  decaying  wood ;  it  fre- 
quently consists  of  multitudes  of  whitish  jointed  hyph*. 
which  are  loosely  interwoven,  but  in  some  cases  they  be- 


HYMENOMYC&TES. 


327 


come  densely  felted  into  tough  masses  five  to  ten  or  more 
millimetres  in  thickness,  and  of  many  centimetres  in 
breadth  and  length ;  it  frequently  also  becomes  compacted 


Fig.  226. — A,  cross-section  of  the  gills  or  lamella;  (/),  of  Agaricus  camptsttris ;  h, 
portion  of  pileus  ;  B,  section  of  one  of  the  gills,  more  highly  magnified  ;  t.  the  cen- 
tnil  tissue  of  the  gill  (trama) ;  sh,,  the  snb-hyinenial  layer  of  short,  rounded  cells; 
/t !t.  hyineniiim.  C',  a  small  portion  of  B,  more  highly  magnified  (  <  550) ;  t.  trama  ; 
sh,  siib-hyinenwl  layer;  q.  young  basidiu  nnd  paraphyses  ;£',  basidium  with  spores 
in  earliest  stage ;  x",  basidium  with  spores  nearly  ripe  ;  *'",  basidinm  with  ripe 
spores  ;  s"",  basidium  from  which  the  ripe  spores  have  fallen. — After  Sachs. 

into  cylindrical  root-like  forms  (Fig.  225,  A,  m).  Upon  the 
mycelium  there  arise,  after  a  longer  or  shorter  period  of  vege- 
tation, small  rounded  or  oblong  masses,  the  young  sporo- 


328  SOTANT. 

carps.  These  are  composed  of  parallel  vertical  hyphae, 
which  grow  upward,  and  finally  bend  out  laterally,  or  send 
out  lateral  branches  at  the  top,  forming  the  umbrella-shaped 
pileus  common  in  many  of  the  genera  (Fig.  225,  V.,  7i). 

425. — In  the  common  Mushroom  (Agaricus  campestris) 
the  young  sporocarp  is  at  first  composed  of  a  mass  of  similar 
hyphae  (Fig.  225,  7.)  ;  somewhat  later,  however,  an  annular 
opening  a  little  below  the  apex  is  visible  in  a  longitudinal 
section  (Fig.  225,  //.,  ?) ;  tnis  enlarges,  and  the  overlying 
tissue  becomes  the  pileus  (Fig.  225,  ///.,  IV.,  and  V.,  h), 
while  that  between  the  opening  and  the  margin  of  the  sporo- 
carp becomes  the  "veil"  (Fig.  225,  IV.  and  V.,  v),  which 
finally,  by  the  rapid  expansion  of  the  pileus,  becomes  rup- 
tured, leaving  an  annular  fragment  (the  ring,  orannulus)  sur- 
rounding the  stalk  of  the  fully  developed  sporocarp.  Upon 
the  under  surface  of  the  pileus  the  hyphae  form  a  great 
number  of  thin  radiating  plates  or  lamellae,  the  so-called 
gills,  and  upon  their  surfaces  there  develops  an  extended 
hymenial  layer.  The  hymenium  consists  of  elongated  cells, 
which  are  slightly  club-shaped,  and  placed  closely  side  by 
side  perpendicular  to  the  gill  surfaces  (Fig  226,  B  and  (7). 
Some  of  these  cells,  the  basidia,  are  somewhat  longer  than 
the  rest,  and  have,  in  this  species,  two,  and  in  most  others, 
four,  slender  projections,  upon  which  spores  (basidiospores) 
are  eventually  produced  (Fig.  226,  C,  s',  s",  s'").  Here  and 
there  upon  the  hymenium  there  may  be  found  larger  bladder- 
shaped  cells,  looking  like  overgrown  sterile  basidia ;  their 
significance  is  not  known,  and  they  have  received  the  name 
of  Cystidia  (Fig.  226«).  In  some  other  genera  the  hyme- 
nium, instead  of  extending  over  lamellae,  is  found  lining  the 
walls  of  vertical  pores,  as  in  Polyporus,  or  covering  depen- 
dent spines,  as  in  Hydnum,  or  spread  out  on  the  smooth 
surface  of  the  sporocarp,  as  in  Stereum.  • 

426. — The  development  of  the  spores  of  the  Hymeno- 
mycetes  takes  place,  according  to  De  Bary,*as  follows  :  The 
young  basidia,  which  have  much  the  shape  of  the  young  asci 

*  "  Morphologic  und  Physiologie  der  Pilze,  Flechten,  und  Myxomy- 
ceten,"  1865,  p.  Ill,  et  seq. 


IIYMENOM7CETES. 


329 


of  the  Ascomycetes  (Fig.  196,  a,  b,  and  c),  are  filled  with 
granular  protoplasm  ;  when  the  projections  (sterigmata) 
make  their  appearance,  the  protoplasm  in  the  basidium 
passes  into  them,  and  is  slightly  withdrawn  from  its  lower 
end.  Each  sterigma  swells  at  its  extremity  into  a  bladder- 
shaped  body,  the  young  spore,  and  as  it  enlarges  the  proto- 
plasm of  the  basidium  is  passed  into  it.  By  the  time  the 
spores  are  full  grown  the  protoplasm  has  nearly  all  disap- 
peared from  the  basidia.  The  spores,  when  ripe,  separate 
themselves  from  the  sterigmata  by 
a  transverse  partition,  and  soon 
fall  off. 

427. — With  regard  to  the  ger- 
mination of  the  spores  but  little  is 
known,  but  in  Coprinus,  according 
to  Van'Tieghem,*  they  give  rise  to 
a  mycelium,  and  this  is  probably 
the  case  with  all. 

428. — The  existence  of  sexual 
organs  in  the  Hymenomycetes  is 
still  involved  in  much  doubt.  (Er- 
sted  describedf  long  ago  certain 
bodies  which  he  discovered  on  the 
mycelium  of  Agaricus  variabilis 
just  before  the  formation  of  the 
sporocarp.  They  are  described  as 
consisting  of  two  kinds  of  cells, 
viz.,  (1)  single  curved,  and  almost  reniform cells,  which  grow 
out  from  the  sides  of  the  hyphae  ;  they  are  .02  mm.  long  and 
about  .  01  mm.  in  diameter,  and  appear  to  be  separated  from 
the  hyphae  from  which  they  grow  by  a  septum  ;  (2)  very  slen- 
der filiform  cells,  which  grow  out  from  beneath  the  former. 
OErsted  saw  (in  two  instances)  a  union  of  these  two  organs. 
He  came  to  the  conclusion  that  the  sporocarp  was  the  result 
of  a  growth  due  to  several  such  unions — i.e.,  that  the  sporo- 
carp was  the  result  not  of  one,  but  of  several  fertilizations. 


Pi"  226a. — A  small  portion  of 
the  hymenium  of  Gomphidium. 
a,  sterile  cells  ;  b,  basidia— each 
with  some  of  the  spores  attached; 
c,  a  cystidium.— After  De  Seynes. 


*  "Comptes  rendus,"  1875. 

f  In  the  work  already  cited  in  the  foot-note  on  p. 


330  BOTANY. 

For  some  reason  these  observations  have  fallen  out  of  notice, 
and  they  still  are  wanting  confirmation.  The  close  resem- 
blance of  these  organs,  as  described,  to  the  sexual  organs  of 
Peziza,  renders  it  probable  that  they  are  actually  sexual  in 
their  nature. 

429. — More  recently  Eeess  has  published  the  results  of 
his  observations  upon  Coprinus  stercorarius.*  He  found 
that  upon  short  lateral  branches  of  the  young  myceliTim 
many  minute  bodies  (spermatia)  are  produced  ;  these,  after 
falling  off,  come  in  contact  with  a  thick  three-celled  body 
(carpogonium  ? ),  which  they  are  supposed  to  fertilize. 
Afterward  from  the  basal  cell  numerous  filaments  grow 
out,  and  eventually  give  rise  to  the  sporocarp.  f 

(a)  In  the  study  of  the  tissues  of  the  Hymenomycetes  young  and 
perfectly  fresh  specimens  are  the  best ;  where  this  is  impossible  they 
may  be  preserved  in  alcohol,  and  then  studied  at  leisure.     Thin  trans- 
verse sections  of  the  gills  will  invariably  show  basidia  and  spores. 

(b)  The  genera  of  this  order  differ  not  only  as  to  the  disposition  of 
the  hymenium,but  also  as  to  the  form  of  the  sporocarp.     With  respect 
to  the  latter,  it  is  symmetrical  and  stalked,  as  in  the  common  Mush- 
room, or  unsymmetrical  and  sessile,  as  in  many  species  of  Polyporus. 
The  texture  of  the  sporocarp  also  varies  from  soft  and  deliquescent  to 
hard  and  durable. 

(c)  The  more  common  genera  are  Agaricus,  with  several  hundred 
species,  Boletus,  Polyporus,  Hydnum,  Stereum,  and  Clauaria. 

(d)  Nearly  related  to  the  Hymenomycetes,  if  not  indeed  to  be  included 
with  them,  are  the  TKEMELLINI,  which  are  gelatinous  fungi,  upon  whose 
uneven  surfaces  is  spread  an  hymenial  layer,  composed  of  basidia  re- 
sembling those  of  Hymenomycetes.     Sachs  regards  these  plants  as  con- 
stituting a  group  related  to,  but  distinct  from,  Hymenomycetes. 

(e)  Many  species  are  edible  and  nutritious.    Agaricus  campestris,  the 
Mushroom,  is  commonly  cultivated.     Dr.  M.  A.  Curtis  found  in  North 

*Dr.  Max  Eeess,"  Zur  Befruchtungsvorgang  bei  den  Basidiomyceten," 
1875.  Van  Tieghem,  in  "  Comptes  rendus,"  1875,  p.  373,  makes  pub- 
lic the  results  of  his  investigations,  which  are  essentially  the  same  as 
those  of  Reess,  but  a  few  months  later  he  withdraws  his  statements  : 
"  Comptes  rendus,"  1875,  p.  877. 

f  It  is  scarcely  necessary  to  refer  to  the  paper  by  W.  G.  Smith  in 
"  Grevillea,"  1875,  p.  53,  in  which  he  describes  a  fertilization  of  the 
spores  by  spermatozoids  developed  by  the  cystidia.  The  many  other 
evident  errors  in  the  paper  make  the  value  of  his  observations  upon 
the  supjxised  organs  of  fertilization  exceedingly  doubtful 


CHARACE^E.  331 

Carolina  thirty-eight  edible  species  of  Agaricus,  eleven  of  Boletus,  nine 
of  Polyporus,  seven  of  Hydnum,  and  thirteen  of  Clavcuria. 

(/)  Polyporites  Bowmani  of  the  Carboniferous  is  the  oldest  known 
member  of  this  order.  In  the  Tertiary  the  modern  genera  Lenzites, 
Polyporus,  and  Hydnum  are  represented. 


§  V.  CLASS  CHABACE^E. 

430.  —  In  this  small  group  of  chlorophyll-bearing  aquatic 
plants  the  sexual  organs,  while  still  preserving  essentially 
the  structure  common  to  other  Carposporeae,  present  con- 
siderable modifications.  The  female  organ  consists  of  a 
"  central  cell  "  or  carpogonium  (Fig.  227,  c),  which  is  the 
terminal  one  of  a  row  of  cells  (a, 
b,  c,  Fig.  227).  From  the  basal 
cells  there  grow  out  five  elongat- 
ed cells  (d,  d,  Fig.  227),  which 
take  an  upward  direction  and 
surround  the  carpogonium  ;  they 
cohere  laterally,  so  as  to  form  a 
complete  covering.  The  top  of 

,       .  i  Pig.    227,-Development  of    tke 

this  enveloping  sheath  becomes    carpogonium  of  mteUa 
modified  into  a  projecting  crown    ^^^^SS 
of  five  (or  by  division  ten)  more 
or  less  divergent  cells  (i,  t,  Fig. 
227   B;   and    c,   Fig.    228,    A). 


Finally,  the  whole  envelope  be-    dosed  the  central  ceii,c;  i.i,ce\\» 

J'  which  form  a  crown  upon  the  en- 

comes  twisted,  so  that  each  en-  veioping  ceils.  x  aoo.—  After  Sachs. 
yeloping  cell  passes  spirally  around  the  carpogonium  (A, 
Fig.  228). 

431.  —  The  male  organ,  or  antheridium,  consists  of  a 
globular  body  composed  externally  of  eight  spherically  tri- 
angular cells,  called  the  shields,  which  are  united  by  their 
zigzag  margins  (a,  Fig.  228,  A).  From  the  centre  of  each 
shield  there  projects  into  the  cavity  of  the  antheridium  a 
cylindrical  cell  (manubrium),  and  upon  each  of  these  there 
are  borne  large  numbers  (twenty  to  twenty-five)  of  long 
coiled  and  bent  many-celled  filaments  (b  and  c,  Fig.  229). 
Each  filament  contains  from  one  to  two  hundred  cells, 


332 


BOTANY. 


which  are  at  first  filled  with  granular  protoplasm  ;  after- 
ward each  cell  develops  a  single  spirally  coiled  spermato- 
zoid.  When  the  antheridium  is  mature — i.e.,  when  the 
spermatozoids  are  fully  formed — the  shields  separate  from 
each  other,  and  thus  expose  the  filaments  (Fig.  229).  The 
spermatozoids  escape  by  the  rupture  of  the  walls  of  the  fila- 
ment cells  ;  each  consists  of  a  slender  spiral  thread  of  proto- 
plasm, thicker  at  one  end  than  the  other,  and  provided  at 

the  more  attenuated  ex- 
tremity with  two  very  del- 
icate and  greatly  elongated 
cilia  (Fig.  229,  d).  By 
means  of  these  cilia  the 
spermatozoids  movf 
through  the  water  with  a 
spiral  rotary  motion. 

432.— Fertilization  takes 
place  by  the  entrance  of 
spermatozoids  through  the 
orifice  between  the  diverg- 
ing cells  of  the  crown  :  they 
come  in  contact  with  the 
a?ex  of  the  carpogonium, 
rl  "  where  the  cell-wa11  is  aP- 

ing  cells  ;  c,  crown  of  five  cells  at  a|.ex ;  /3,  pareiltly  absent  ;"  as  a  re- 
sterile  lateral  leaflets ;  8'  large  lateral  leaf-  , ,  .  , ,  •  , , 
let  near  the  fruit ;  £'',  bracteoles  springing  «llt  of  this  Union,  the 
fiom  the  basal  node  of  the  reproductive  or-  enveloping  Cells  become 
gans.  B,  a  young  amheridmm,  a,  and  ».,.«_*  njv  j  j 
young  carpogonium.  sk:  w.  nodal  cell  of  thicker  Walled,  hard,  and 

dark -colored,    forming    a 
!  Sx'S'SS  dense  and  resisting  coating 
Sach8-  to  the  fully  formed  carpo- 

spore  within.  The  seed-like  sporocarp  thus  formed  soon 
separates  itself  from  the  parent  plant  and  falls  to  the  bot- 
tom of  the  water,  where  it  remains  until  the  advent  of  favor- 
able conditions  for  germination. 

433.— In  germination  the  sporocarp  gives  rise  first  to  a 
simple  structure  consisting  of  a  single  row  of  cells  (the  pro- 
embryo),  and  from  this  the  more  complex  sexual  plant  is 
developed  by  the  growth  of  a  lateral  bud-cell.  The  sexual 


333 


plant  is  composed  of  a  jointed  stem,  which  bears  whorls  of 
leaves  at  regular  intervals.  The  stem  is  one-celled  in  trans- 
verse section,  as  in  Nitella,  or  it  has  a  large  axial  cell,  which 
is  surrounded  by  many  long  narrow  ones,  which  form  a 
cortical  envelope,  as  in  many  species  of  Chara.  In  some 
species  the  stem  and  leaves  become  incrusted  with  lime,  giv- 
ing to  them  a  good  deal  of  hardness  and  brittleness. 

'(a)  The  class  is  readily  divisible  into  two  orders  —  Nitelleae  and 
Chareae.* 

Order  Nitelleae. — In  this  order  the  stem  and  leaves  are  always 
naked — i.e..  hot  cor- 
ticated ;  the  leaves 
are  in  whorls  of 
five  to  eight,  and 
bear  large  leaflets, 
which  are  often 
many  -  celled.  The 
sporocarps  arise  sin- 
gly or  in  clusters  in 
the  forkings  of  the 
leaves,  and  each  has 
a  crown  consisting 
of  two  superimposed 
whorls  of  five  cells 
each. 

These  delicate 
plants  occur  in 
ponds  and  streams, 
and  are  rarely  more 
than  a  few  centi- 
metres in  height.  V\K.«».- Chora  f^gUia.  a,  an  isolated  shield,  m,  seen 
Two  genera — Nitella  from  within,  with  inann  >rium  bearing  the  filaments,  &,'  in 
nni\  Tnliinflln  nrp  which  the  spermatu/.oidtt  nre  developed  ;  c,  a  small  portion 
and  lolypella  —  e  Qf  Qae  of  ^  fl]aments  ,h  .  ,,perraatFozoids  not  shown ;  d, 
distinguished  by  the  two  free  spermatozoids.  a  and  b  X  50  ;  o  and  d  X  300.— 
position  of  the  anthe-  After  Thuret- 

ridium,  which  is  terminal  upon  the  single  node  of  the  primary  leaf  in 
the  former,  while  in  the  latter  it  is  lateral,  and  the  primary  leaf  has 
two  or  three  nodes. 

The  species  of  Nitella  (ten  to  fifteen  of  which  are  American)  are  ar- 

*  What  follows  is  mainly  from  a  synopsis  of  the  Characese,  furnished 
for  this  work  by  Dr.  T.  F.  Allen,  the  author  of  "  Characeae  Americanse," 
now  issuing  in  numbers.  Use  has  also  been  made  of  Dr.  B.  D.  Hal- 
sted's  paper  on  the  "  Cassification  and  Description  of  the  American 
species  of  CharaceaR,"  published  in  Proc.  Boston  8oc.  Nat.  Hist  ,  1879, 


334  BOTAN7. 

ranged  under  three  tribes  ;  our  more  common  species  only  are  given 
below. 

Tribe  A. — Mono,  throdactyke,  with  the  terminal  segments  of  the 
leaves  one-celled. 

JV.  flexttis,  JV.  translucens,  Jf.  gelatinosa. 

Tribe  B. — Diarthrodacfyla,  with  the  ultimate  segments  of  the 
leaves  two-celled. 

y.  gracilis,  JV.  tenuissima. 

Tribe  C.—Poly<irthrodactyla>,  with  the  ultimate  segments  of  the 
leaves  three  to  six-celled. 

N.  cnpittata,  N.  intricata. 

The  genus  Tolypella  contains  but  one  known  American  species,  T. 
nidifica. 

Order  Charese. — In  this  order  the  stem  and  leaves  are  sometimes 
naked,  and  sometimes  corticated ;  the  leaves  are  in  whorls  of  six  to 
twelve,  and  their  bracts  or  leaflets  are  always  one-celled.  The  sporo- 
carps  arise  upon  the  upper  side  of  the  leaves,  and  each  has  a  crown  of 
one  whorl  of  five  cells. 

These  plants  resemble  the  Nitelleae  in  size  and  habit.  The  species 
are  separated  into  two  genera,  Lychnothamnus  and  Chara.  The  former 
has  no  representatives  in  America;  it  may  be  distinguished  by  the  an- 
theridia  being  by  the  side  of  the  carpogonia  instead  of  below  them,  as 
is  the  case  in  Chara. 

The  species  of  Chara  are  arranged  under  three  tribes  ;  there  are 
about  a  dozen  representatives  in  America,  the  more  important  of  which 
are  here  given. 

Tribe  A.—Astephance,  with  no  circle  of  stipules.  No  American 
representative. 

Tribe  B. — Haplostephance,  with  a  circle  of  stipules  consisting  of  a 
simple  series  of  cells. 

Ch.  coronata,  Ch.  Hydropitys. 

Tribe  C.—Diplostephance,  with  the  stipular  ring  double. 

Ch.fatida,  Ch.fragUin,  Ch.  gymnopus. 

(6)  The  genus  Chara  is  a  very  old  one  ;  some  species  occur  in  the  Sec- 
ondary (Jurassic)  strata,  and  in  the  Tertiary  (of  Europe)  they  are  very 
abundant,  no  less  than  thirty-seven  species  being  recorded  by  Schim- 
per.*  According  to  Lesquereux  f  no  fossil  species  of  Characeae  have 
yet  been  discovered  in  America,  which  is  a  remarkable  fact,  for  at 
the  present  time  the  plums  of  this  group  are  as  abundant  here  as  in 
Europe,  and  the  sporocarps  possess  great  durability  and  are  likely  to 
be  preserved  as  fossils. 

*  "  Traite  de  Paleontologie  Vegetale,"  par  W.  Ph.  Schimper,  Paris, 
1869-1874. 

f  "  Contributions  to  the  Fossil  Flora  of  the  Western  Territories ; 
Part  II.,  The  Tertiary  Flora,"  by  Leo  Lesquereux,  Washington,  1878. 


CLASSIFICATION  OF  THALLOPHYTES.  335 

ARRANGEMENT  OF  THE  CLASSES  OF  THE  CARPOSPORE.E. 


VI.   THE  CLASSIFICATION  OF  THALLOPHYTES. 

(1.)  The  classification  of  the  Thallophytes,  outlined  in  the  preceding 
pages,  is  essentially  that  given  by  Sachs  in  the  fourth  edition  of  his 
"  Lehrbuch."  Sachs,  however,  considered  the  Protophyta,  Zygosporeae, 
Oosporeae,  and  Carposporese  to  be  Classes,  whereas  in  this  book  they  are 
raised  to  Divisions,  co-ordinate  with  Bryophyta,  Pteridophyta,  and  Pha- 
nerogamia.  It  is  evident,  even  from  the  hasty  examination  sketched  in 
the  preceding  pages,  that  there  are  three  well-marked  kinds  of  repro- 
ductive apparatus  in  the  Thallophytes,  which  are,  to  a  considerable 
degree,  distinct.  There  are,  of  course,  here  and  there  cases  in  which 
one  kind  merges  into  another,  but  this  is  no  more  than  is  to  be  observed 
in  everything  else  throughout  both  the  vegetable  and  animal  king- 
doms. After  making  all  due  allowance  for  the  doubtful  cases,  the  fact 
yet  remains  that  there  are  three  kinds  of  reproductive  apparatus  in  the 
Thallophytes,  which  are  as  readily  distinguishable  as  are  those  of  the 
Cormophyte  Divisions,  Bryophyta,  Pteridophyta,  and  Phanerogamia. 

(2.)  Of  the  differentiation  of  tissues  we  know  less ;  but  enough  is 
known  to  warrant  the  statement  that,  as  in  the  Divisions  of  theCormo- 
phytes,  there  is  a  progressive  increase  in  complexity  as  we  pass  from 


336  BOTANY. 

the  lower  to  the  higher  Thallophytes.  Thus  the  Zygosporeae,  as  a  rule, 
are  single  cells  (Desmidiacece  and  Diatomacece),  or  rows  of  cells  (Zygne- 
macece,  etc.),  of  simple  structure ;  the  Oosporeae  are  generally  single 
cells  of  a  complex  structure  (CcdoblasteoB),  rows  of  differentiated  cells 
(CEdogoniecR),  or  even  tissues,  forming  structures  which  have,  in  some 
cases,  a  close  approximation  to  stems  and  leaves  (FucacecB) ;  the  Car- 
posporeae  are  all  multicellular  ;  the  lower  ones  are  made  up  of  rows  of 
cells,  which  are  generally  united  into  a  plant-body  (sporocarp  of  Asco- 
mycetes  and  Batddiomycetes),  while  in  the  higher  ones  there  are  tissues 
which  form  stems  and  leaves  (some  Floridece  and  Characece). 

(3.)  It  can  scarcely  be  doubted,  then,  that  the  three  Thallophyte  groups 
Zygosporeae,  Oosporese,  and  Carposporese,  are  as  much  entitled  to  rank  as 
Divisions  as  are  those  of  the  Cormophytes.  The  Protophyta  constitute 
a  provisional  group,  but  while  it  is  very  likely  that  many  of  the  forms 
now  included  in  it  may  be  placed  elsewhere  when  they  are  better  un- 
derstood, it  is  extremely  improbable  that  all  will  be  thus  disposed  of  ; 
it  seems  more  probable  that  the  group  may  be  preserved,  very  likely  in 
a  modified  form,  as  a  sort  of  primary  Division. 

(4.)  The  arrangement  followed  in  this  book  may  be  made  plainer  by 
the  subjoined  table.  The  Classes  only  (printed  in  SMALL  CAPITALS) 
are  given,  excepting  where,  for  obvious  reasons,  it  is  necessary  to 
particularize  more  closely  (Orders  and  genera  in  lower  case).  The 
groups  on  the  left  are  composed  of  chlorophyll-bearing  plants,  and 
are  regarded  as  the  proper  representatives  of  the  Divisions.  The 
groups  on  the  right  hand  (printed  in  italics)  are  composed  of  plants 
which  are  parasitic  or  saprophytic,  and  which,  as  a  consequence,  show 
more  or  less  of  degradation  in  their  vegetative  parts  ;  the  absence  of 
chlorophyll  here,  as  in  the  case  of  parasitic  Phanerogams,  is  an  accom- 
paniment of  structural  changes  in  the  vegetative  parts  of  the  plant, 
which  are  always  degradatioual  in  their  nature. 


PROTOPHYTA. 
MYXOMYCETKS. 


SCHIZOMYCKTBS. 

SaccJiaromycetes  (?). 


CYANOPHYCE.K. 

ZYGOSPOREAE. 

Pandorina,  etc. 

CONJUGATE.  . .  Mucwini. 


CLASSIFICATION  OF  THALLOPHYTES.  337 

OOSPORE.E. 


Volvox,  etc. 
CEDOGONIE.E. 


CARPOSPORE^E. 
Coleochaete. 
FLORIDE^E. 

....................................  ASCOXYCBTES. 

Uredinecs  (?). 
UstilaginecB  (?). 

......................................  BA.8IDIOMYCETE8. 

CHAKACKiE. 

It  will  be  instructive  to  compare  the  foregoing  with  other  attempts 
at  an  arrangement  of  the  Thallophytes. 

(5.)  The  arrangement  which  has  long  been  followed,  and  which  is 
still  in  use  in  most  English  books,  is  that  which  divides  the  Thallo- 
phytes (considered  a  class)  into  three  orders,*  viz., 

1.  Algae,  aquatic  and  chlorophyll-bearing. 

2.  Fungi,  terrestrial,  and  destitute  of  chlorophyll. 

3.  Lichenes,  terrestrial,  and  containing  green  gonidia. 
Berkeley's  arrangementf  differs  from  this  only  in  the  relative  rank  of 

the  groups. 
Alliance  I.  Algales  (Alga). 

Amaucell.  M^cetale, 

Algae  have  usually  been  divided  into  three  groups  (sometimes  called 
sub-orders),  as  follows  : 

1.  Chloi'ospermea,  including  all  the  chlorophyll  -bearing  plants  of  the 
Protophyta  and  Zygosporeae,  and  all  the  Oosporeae,  excepting  Fucacece. 

2.  Rhodospermece,  nearly  equivalent  to  the  Floridece. 

3.  Melanospermece,  including   the  Fucacece,  Phaospore®,  and  some 
other  plants. 

(6.)  Fungi  are  still  arranged  in  most  English  books  in  six  groups 
(called  orders,  sub-orders,  or  even  families),  as  follows  4 
1.  Ascomycetes,  nearly  as  in  this  book. 

*  See  Hooker's  "  Synopsis  of  the  Classes,  Sub-classes,  Cohorts,  and 
Orders,"  in  the  English  edition  of  Le  Maout  and  Decaisne's  "  General 
System  of  Botany,"  1872,  p.  1023. 

f  "  Introduction  to  Cryptogamic  Botany,"  1857,  p.  81. 

J  See  Berkeley's"  Introduction,"  already  cited  ;  Berkeley's  "Outlines 
of  British  Fungology,"  1860;  Cooke's  "  Hand-book  of  British  Fungi," 
1871;  Cooke  and  Berkeley's  "Fungi,  their  Nature,  Influence,  and 
Uses,"  1874;  and  Fries'  "  Systema  Mycologicum,"  1821. 


338  BOTANY. 

2.  Physornycetes,  including  the  Mucorini  and  Saprolegniacece. 

3.  Hyphomycetes,  including  Peronosporece,  Penicillium,    and   many 
imperfect  forms. 

4.  Coniomycetes,  including  Uredinece  and  Ustilaginece,  and  in  addi- 
tion a  great  number  of  imperfect  stages  of  Ascomycetes. 

5.  Ga&teromycetes,  as  in  this  book,  with  the  addition  of  Myxomy- 
cetes. 

6.  Hymenomycetes,  as  in  this  book,  and  including  the  Tremettini. 

De  Bary*  arranged  Fungi  under  four  groups,  as  follows  : 

1.  Phycomycetes. 

Saprolegniacece.    Peronosporece.    Mucorini. 

2.  Hypodermiae. 

Uredinete.     UstilagineoR. 

3.  Basidiomycetes. 

TremeUini.     Hymenomycetes.     Gasteromycetes. 

4.  Ascomycetes. 

Protomycetes.      Tvberacew.     Onygenece.     Pyrenomycetes.    Dte- 

comycetes. 

In  both  the  foregoing  arrangements  of  Fungi  the  Lichens  are  omitted, 
they  being  regarded  as  of  a  different  nature. 

(7.)  In  1872  Cohn  published!  an  outline  of  a  classification  of  the  Cryp- 
togams in  which  the  old  distinctions  between  Algae,  Fungi,  and  Lich- 
ens were  abandoned.  He  considered  the  Tballophytes  as  constituting 
a  single  class,  co-ordinate  with  Bryophyta,  Pteridophyta,  and  Phanero- 
gamia,  and  divided  it  into  seven  orders,  and  each  of  these  into  many 
families  ;  the  latter  are  in  most  cases  equivalent  to  what  are  called 
orders  in  this  book.  The  families  in  Roman  contain  chlorophyll,  those 
in  italics  are  chlorophyll-less. 

Class  Thallophyta. 
ORDER  I.    SCHIZOSPORE^I. 

1.  Schizomycetes.  2.  Chroococcacese.  3.  Oscillatoriaceae.  4.  Nos- 
tocaceae.  5.  Rivulariaceae.  6.  Scytonemaceae. 

ORDER  II.    ZYGOSPOREJE. 
1.  Diatomaceae.     2.  Desmidiaceae.     3.  Zygnemaceae.    4.  Mucoraceas. 

*  In  Streinz:  "  Nomenclator  Fungorum,"  1861,  p.  722,  and  also  in 
"  Morphologic  und  Physiologic  der  Pilze,  etc.,"  1865,  preface,  p.  6. 

f  Ferdinand  Cohn,  "  Conspectus  familiarum  cryptogamarum  secun- 
dum  methodum  naturalum  dispositarum,"  in  "  Hedwigia,"  February, 

1872. 


CLASSIFICATION  OF  THALLOPHYTES.  339 

ORDER  III.    BASIDIOSPORE^B. 

SECTION  1.  HYPODERMICS. 
1.    Uredinacece.    2.   Ustilaginaceae. 

SECTION  2.  BASIDIOMYCETES. 

3.  Tremettacece.    4.  Agaricacece  (Hymtnomycetes).    5.  Lycoperdacew 
( Gasteromyeetes). 

ORDER  IV.    ASCOSPORE^J. 

1.  Tuberacea.  2.  Onygenacece.  3.  Erysiphacea.  4.  SpJuzriaccce  (Py- 
renomycetes).  5.  Hehellacece.  6.  Lichenes  (excluding  Collemacese). 

ORDER  V.   TETRASPORE^E  (FLORIDE^l.) 
1.  Bangiaceae.     2.  Dictyotacese.     3.  Ceramiacese.      4.    Nemaliaceae. 
5.  Lemaniaceae.      6.  Sphserococcaceas       7.  Melobesiaceaa.      8.  Rhodo- 
melacese. 

ORDER  VI.   ZOOSPORE^:. 

1.  Palmellaceae.  2.  Confervaceae.  3.  Ectocarpeaa.  4.  Sphacelari- 
ace;c.  5.  Sporochnaceaa.  6.  Laminariacese. 

ORDER  VII.  OOSPORE^I. 
SECTION  1.  LEUCOSPORE^E. 
1.  Chytridiacece,    2.  Peronosporacece,     3.  Saprolegniacece. 

SECTION  2.   CHLOROSPORE^E. 

4.  Volvocaceae.     5.  Siphonaceae.      6.  Spliaaropleaceaa.     7.    ffidogoni- 
aceae.    8.  ColeochaetaceaB. 

SECTION  3.  PH^EOSPORE^:. 
9.  Tilopterideae.    10.  Fucaceas. 

(8.)  In  1873  Fischer  proposed  an  arrangement*  of  the  Thallophytes 
which  in  many  respects  is  like  that  of  Sachs.  Like  the  latter,  Fischer 
divides  the  Thallophyta  (co-ordinate  with  Cormophyta)  into  four 
classes,  composed  in  each  case  of  chlorophyll-bearing  and  chlorophyll- 
free  plants,  the  algae  and  fungi.  Instead,  however,  of  considering  the 
fungi  as  degraded  forms,  he  regards  them  as  constituting  with  the 
algae  two  parallel  but  entirely  distinct  genetic  lines.  The  Myxomy- 
cetes  he  "places  in  a  third  genetic  line,  nearest  to,  but  still  distinct  from, 
the  fungi. 

*  Given  in  Sachs'  "  Lehrbuch,"  fourth  edition,  p.  248.  The  groups 
given  under  each  class  are  of  very  unequal  value. 


340  BOTANY. 

THALLOPHYTA. 
(ALG^K.)  (FUNGI.)  MTXOMYCETES. 

CLASS  I. 

Without  sexual  reproduction. 
Phycocbromaceae.  Saccliaromycetea. 

CLASS  II. 

Sexual  reproduction  by  copulation. 
Diatouiese. 
Conjugateae.  Zygomyrcte*. 

CLASS  III. 

Producing  oospores  after  fertilization. 
Palmellaceae.  Peronosporev. 

Sipboneae.  Saprolfgniacea. 

Confervae. 
Fucacese. 
Coleocbaeteae. 
Cbaracese. 

CLASS  IV. 

Producing  a  complex  fruit-body  [sporocarp]  after  fertilization, 
Floridese.  Ascomycetes. 

Basidiomycete* 


CHAPTER    XVIII. 

BKYOPHYTA. 

434. — This  division  includes  plants  of  a  much,  greater  de- 
gree of  complexity  than  any  of  the  preceding.  In  all  there 
is  a  well-marked  alternation  of  sexual  and  asexual  genera- 
tions. The  first  generation — that  is,  the  one  proceeding 
from  the  spore — bears  the  sexual  organs,  and  hence  it  is 
called  the  sexual  generation.  After  fertilization,  and  as  a 
result  of  it,  there  grows  a  sporocarp,  which  consists  of  a  case 
or  body,  in  which  spores  arise  asexually  ;  hence  this  is  called 
the  asexual  generation.  From  these  spores  the  sexual  gen- 
eration is  again  produced. 

435. — The  production  of  the  sexual  generation  may  take 
place  either  directly  or  indirectly.  In  the  first  a  thallus-like 
structure  is  produced  directly  from  the  germination  of  the 
spore,  as  in  some  of  the  Liverworts  (Anthoceros,  Frullania, 
etc.) ;  in  most  Mosses,  however,  there  is  first  produced  from 
the  spore  a  Conferva-like  mass  of  threads,  the  pro-embryo  or 
protonema,  and  upon  this  buds  arise,  which  grow  into  the 
leafy  sexual  generation. 

436. — The  sexual  organs  of  Bryophytes  consist  of  arche- 
gonia  and  antheridia.  The  former  are  flask-shaped  bodies, 
whose  walls  are  composed  of  a  single  layer  of  cells.  In  the 
bottom  of  the  cavity  of  each  archegonium  is  a  naked  mass  of 
protoplasm,  the  germ-cell,  which  is  the  essential  part  of  the 
female  organ.  The  antheridia  are  of  various  shapes  ;  but 
they  are  generally  club-shaped,  or  somewhat  spherical,  stalked 
bodies,  whose  walls,  like  those  of  the  archegonia,  are  com- 
posed of  a  single  layer  of  cells.  The  antheridia  are  filled 
with,  usually,  a  great  number  of  sperm-cells,  each  of  which 
contains  a  single  spirally  coiled  spermatozoid. 


342  BOTANY. 

437. — Fertilization  takes  place  by  the  spermatozoids  find- 
ing their  way  down  the  neck  of  the  archegonium  (open  at 
this  time)  and  uniting  their  substance  with  that  of  the  germ- 
cell.  The  first  result  of  fertilization  is  the  formation  of  a 
wall  upon  the  germ-cell,  which  then  begins  to  divide  into 
a  mass  of  cells  by  the  formation  of  diagonal  partitions. 

438. — The  sexual  organs  are  generally  numerous,  and 
they  are  frequently  produced  in  little  clusters  of  several  to- 
gether, surrounded  by  enveloping  leaves  (the  perichcetium), 
thus  forming  a  sort  of  flower.  In  some  species  the  anther- 
idia  and  archegonia  are  in  the  same  flowers  (hermaphrodite), 
while  in  others  they  are  upon  different  parts  of  the  same  plant 
(monoecious),  or  upon  entirely  diffei'eut  plants  (dioecious). 

439. — The  second,  or  asexual,  generation  is  always  devel- 
oped from  the  fertilized  germ-cell  belonging  to  the  first ;  but 
while  it  is  nourished  by  the  latter,  there  is  no  organic  con- 
nection between  the  sexual  and  the  asexual  generations. 
The  asexual  generation  consists  of  a  spore-case,  or  sporogo- 
nium,  with  a  greater  or  less  developed  stalk,  or  seta,  support- 
ing the  former.  The  spore-case  varies  much  in  form  and 
degree  of  complexity,  being  in  some  cases  but  a  globular 
body  filled  with  spores,  while  in  others  its  structure  is  quite 
complex,  and  difficult  to  understand. 

440. — The  spores  are  produced  from  mother-cells,  each  of 
which  gives  rise  by  internal  cell-division  to  four  daughter- 
cells,  the  spores.  The  mature  spores  are  provided  with  a 
double  wall,  the  outer  (exospore)  being  usually  hard  and 
somewhat  roughened,  while  the  inner  (endospore)  is  thin  and 
elastic.  The  interior  of  the  spore  is  composed  of  colorless 
protoplasm,  chlorophyll  granules,  starch,  and  minute  drops 
of  oil.  In  germination  the  endospore  breaks  through  the 
exospore,  and  becomes  prolonged  as  a  narrow  tube,  which  by 
division  gives  rise  to  the  sexual  stage  of  the  plant. 

441. — In  a  portion  of  the  Division  the  plant-body  is  either 
a  true  thallus,  or  a  structure  which  is  best  described  as 
thalloid  in  form  ;  in  all  of  the  Mosses,  however,  and  some  of 
the  Liverworts,  there  is  a  differentiation  into  stem  and  leaf. 

442. — No  true  roots  are  found  in  the  Bryophyta,  but  in 
place  of  them  there  are  root-hairs,  consisting  of  single  cells. 


HEPATIC^!.  343 

or  rows  of  cells ;  these  are  attached  to  the  under  surface  of 
the  thallus,  or  to  the  side  of  the  stem,  and  serve  to  support 
and  fix  the  plant,  as  well  as  to  absorb  nutritious  substances 
for  its  sustenance. 

443. — The  tissues  of  Bryophyta  are  much  more  highly 
developed  than  in  the  preceding  divisions  ;  the  epidermis  is 
in  many  cases  quite  well  defined,  and  here  for  the  first  time 
true  stomata  make  their  appearance  (paragraph  119, page  91). 
The  greater  part  of  the  plant-body  is  in  most  cases  composed 
of  a  well-developed  parenchyma,  composed  of  thin-walled 
cells,  which  are  compacted  into  a  true  tissue.  There  is, 
moreover,  a  slight  indication  of  the  development  of  a  fibro- 
vascular  system  in  the  elongated  bundles  of  cells  which  oc- 
cur in  the  leaf  veins  and  the  axial  portions  of  the  stems  of 
some  of  the  species.  The  cells  immediately  beneath  the  epi- 
dermis are  much  thickened  in  some  cases,  so  as  to  form  a 
strengthening  tissue.  This  may  be  regarded  as  a  simple 
kind  of  sclerenchyma. 

444 — The  Bryophytes  are  usually  divided  into  two  classes, 
the  Liverworts  (Hepaticce)  and  the  Mosses  (Musci). 

§  I.   CLASS  HEPATIC^:. 

445. — In  this  class  of  plants,  commonly  called  the  Liver- 
worts, the  plant-body  is  for  the  most  part  either  a  true 
thallus  or  a  thalloid  structure.  Even  when  there  is  a  differ- 
entiation into  stem  and  leaves,  it  still  retains  some  of  the 
peculiarities  of  the  thallus  ;  thus  in  most  cases  the  plant- 
body  has  two  distinct  and  well-marked  surfaces,  an  upper  or 
dorsal,  and  an  under  or  ventral  one,  the  latter  bearing,  for 
the  most  part,  the  rhizoids,  by  means  of  which  the  plant  is 
fixed  to  the  ground.  Growth  is  alwavs  from  an  apical  cell. 

446. — The  tissues  of  the  Liverworts  are  quite  simple,  and 
even  in  the  leaf-bearing  kinds  there  is  but  little  differentia- 
tion ;  the  leaves,  when  present,  have  no  midrib  or  other  veins, 
but  consist  of  a  simple  plate  of  cells.  The  mode  of  branch- 
ing is  dichotomous  in  the  lower  species — i.e.,  those  with  a 
thallus  or  thalloid  plant-body — while  in  those  which  have 
stem  and  leaves  it  is  lateral  and  monopodial. 


344 


BOTANY. 


447. — The  leaves,  when  present,  are  usually  in  two  rows 
(distichous),  and  are  either  opposite  or  alternate  ;  they  are 
entire,  serrate,  or  even  lobed.  There  is  frequently  a  third 
row  of  leaves  (called  amphigastria)  on  the  under  side  of  the 
stem. 

448. — Most  Liverworts  are  small  in  size,  ranging  from  a 
few  millimetres  to  several  centimetres  in  length.  They 
grow  for  the  most  part  in  moist  places,  upon  the  ground,  or 
upon  rocks,  or  the  bark  of  trees.  All  are  chlorophyll-bear- 


Pig.  230. — Jfarchantia  polymarpha.  A,  young  thnllns.  B,  an  older  thallus,  with  one 
gemma-cup  ;  -e,  v,  emargmate  apical  region  of  the  two  young  branches  of  the  thallns. 
C,  a  two-lobed  thallus,  oearing  gemma-cap*.  D,  a  portion  of  the  upper  surface  of  a 
thallns  (magnified),  showing  the  lozenge-shaped  areohe,  each  with  a  central  stoma,  up. 
I.  to  VI.,  development  of  the  genniur.  /.,  very  young  ;  //.,  the  terminal  ci-ll  divided 
trunsvi  rsely  ;  III.,  a  later  stage,  with  divisions  in  various  directions  ;  IV.,  V.,  still 
later  stages  ;  VI.,  outline  of  a  fully  developed  gemma  ;  when  it  grows  the  new  shoots 
will  start  out  right  and  left  from  the  two  depressions  on  its  Bides. — After  Sachs. 

ing  plants,  and   they  are  usually  of  a  green  or  brownish 
green  color. 

449.  —  The  asexual  reproduction  of  Liverworts  takes 
place  by  means  of  bodies  of  a  peculiar  kind,  called  gemmae, 
which  are  usually  produced  in  special  organs.  This  mode  of 
reproduction  is  well  illustrated  in  the  genus  Marchantia,  in 
which  email  cup-shaped  organs  (4  to  6  mm.  in  diameter)  de- 
velop upon  the  upper  side  of  the  thallus  (B  and  C,  Fig. 
230).  In  each  of  these  several  hair-like  papillae  grow  up, 


HEPATIC^!. 


and  by  the  repeated  division  of  their  apical  cells  produce 
upon  each  a  little  flattened  mass  of  cells,  the  gemma.     These 


Fig.  231.— Male  organs  of  Marchantia  polymorpha.  A,  a  portion  of  the  thallus,  t, 
with  two  ascending  branches  bearing  the  antheridial  receptacles,  hu.  B,  vertical  sec- 
tion through  young  antheridial  receptacle,  hu  ;  a,  antheridium  enclosed  in  a  cavity 
which  has  a  narrow  opening,  o;  t,  portion  of  thallus  ;  A,  root-hairs  ;  b,  leaf-like  bod- 
ies seen  in  section.  (7,  a  nearly  ripe  antheridium  ;  at,  its  pedicel ;  w,  the  wall.  D. 
two  spermatozoids.  Variously  magnified.  D  x  800.— After  Sachs. 

gemmae,  when  full-grown,  fall  to  the  ground,  and  grow  di- 
rectly into  new  plants.  In  some  cases  the  gemmae  are  much 
B  /*r>v  n  A  -'"- 


Pig.  232.-Development  of  the  antheridia  of  Riccla  fflauca.  A,  longitudinal  section 
through  the  npex  of  the  thallus :  «,  apical  cell  of  the  thallns  :  b,  scale-like  leaves,  in 
section-  «.  a  very  young  antheridium;  a',  an  okkr  jintheridinm.  surrounded  by  a 
growth  of  thallus  tissue,  ic.  B,  a  young  antheridium,  a,  overarched  by  a  growth  01 
the  thallus.  6",  an  older  antheridium,  in  longitudinal  section,  x  500.— After  Hof- 

simpler  than  those  just  described  ;  in  the  Jungermanniaceas, 
for  example,  they  consist  of  a  few  cells  which  are  spontane- 
ously detached  from  the  tissues  in  the  margins  of  the  leaves. 


346 


BOTANY. 


450. — The  sexual  organs  are  situated  in  depressions  in 
the  upper  side  of  the  thallus,  or  upon  the  sides  or  ends  of 
the  stems,  and  are  surrounded  by  peculiarly  developed  leaves 
(perichaftium)  in  the  leaf-bearing  forms. 

451. — The  antheridium  is  a  more  or  less  globular — usually 
stalked — bodv,  which  arises  from  a  single  cell  (hence  mor- 
phologically a  trichome)  by  the  repeated  subdivision  of  its 
terminal  cells.  Its  outer  wall  consists  of  a  single  layer  of 
cells  (C,  Fig.  231,  w],  and  its  cavity  is  filled  with  a  large 
number  of  sperm-cells,  each  of  which  contains  a  single 
spermatozoid.  The  sperm-cells  escape  by  the  breaking  of 
the  antheridium  wall,  and  in  the  water  in  which  this  always 
takes  place  they  rupture,  and  the  spermatozoids  are  set  free. 
Each  spermatozoid  is  a  spirally  curved  slender  thread  of 


FIO.  233. 


Fig.  233.— Development  of  the  anlheridia  of  Marehantia  jwlymorpka,  in  a  section 
of  a  young  antheridial  disc,  r,  the  growing  anterior  margin  of  the  disc;  f rom  r  to 
the  left  are  shown  the  antheridia  (a,  a,  a.  ft)  in  four  stages  of  development:  at  n/i,  up, 
sp,  are  shown  the  singes  of  development  of  the  stomata  above  the  air  cavities  be- 
tween the  antheridia.  x  300.-After  Hofmeist.  r. 

Fig.  234. — A,  longitudinal  «  ction  of  the  apex  of  the  thallus  of  Riccia  glauca.  fir, 
archegoninm;  c,  germ-cell.  B,  the  unripe  sporogonium,  tg,  surrounded  by  the  calyp- 
tra.  which  still  bears  the  neck  of  the  archegonium,  ar.  A  X  560 ;  B  x  300.— After 
Hofmeister. 

protoplasm,  provided  at   the   anterior  end  with  two  long 
cilia  (Z>,  Fig.  231). 

452. — In  some  cases  the  antheridia  are  developed  singly 
upon  the  upper  surface  of  the  thallus,  as  in  Riccia,  (Fig. 
232).  In  this  particular  case  the  antheridium  is  developed 
directly  from  an  epidermal  cell  (A,  Fig.  232,  a),  and  so  is 
at  first  external ;  it,  however,  soon  becomes  overarched 


HEP  A  TTCM 


34? 


by  the  rapid  growth  of  the  surrounding  tissue  of  the  thallus 

(A,    B,    and    G, 

Fig.    232).       In 

other     eases    the 

antheridia  are  de- 

veloped   in   great 

numbers      upon 

special    branches, 

as  in  Marchantia, 

which  has  a  large 

"  antheridial  disc" 

(A   and   B,   Fig. 

231,  hu),  in  whose 

upper  surface  are 

to  be  found  many 

imbedded  anther- 

idia. That  the  an- 

theridia are  actu- 

ally   external    in 

this  case  also,  be- 

coming apparent- 

ly internal  by  the 

growing  up  of  the 

surrounding     tis- 

sues, is  well  shown 

in   Fig.  233.      In 

still    other    cases 

(e.g.,    in  Junger- 

the 

. 

are    in 

»      ,i 

OI     tne 

In  >™™  o  v/1  nnn-n  ,.  nec-  -i  tne  8ame  wen  niatnre  and  reay  for  fertliza- 
leaves,  and  OCCUr  tion.  VL,  the  base  of  a  fertilized  archegonium,  the 
><i  no-Ivor  in  ornmvj  germ-cell,  /,  divided  into  two  cells  by  a  diagonal  partition. 
blllgiy  01  m  groups.  ^/7  latej  gta  of  the  game>  8howlna  farther  division  of 


,i  .| 

tlie    axils 


.Fig.  235.—  The  archegonin,  and  origin  of  the  sporogo- 
imm  otJfarc/umtia  pofymarpha.  T.  and  //.,  young  arche- 
gonia  ;  «,  germ  cell  ;  si,  lowest  cell  of  axial  row  of  cells. 
///.  and  IV.,  the  same  after  the  formation  of  a  central 
canal  by  the  absorption  of  the  axial  row  of  cells  in  the 
neck-  V-i  tne  8ame  when  niatnre  and  ready  for  fertiliza- 


453.— The 


,    ater  stage  of  the 
ar_    the  germ-cell,  /vand  the  ^bt 


fog 

aing  of  the  growth  of  a 

perianth,  pp.     VIII.,  still  later  stage  of  the  same,  the 
first    Perianth,  pp,  now  enclosing  the  archegonium;  x,  the 
withered  neck  of  the  archegonium.  IX.,  the  unripe  eporo- 
appears  as  a  simple    gonium,  enclosed  in  the  old  walls  of  the  archegonium. 


low  called  the   calyptra, 


papilla,    Composed  st,  the  short,   undeveloped  stalk  of    the    gporogoniiim! 

e  -in  Inside  of  the  sporosroninm  are  the  young  elaters  arranged 

OI     a     Single    Cell,  radially,  and  between  them  are  the  spores.    I.  to  VIII. 

Which,    by    Sllbdi-  X  300;^.  about  30.-Alter  Sachs. 

vision  in  various  directions,  gives  rise  to  a  more  or  less 


348 


HOT  ANY. 


flask-shaped  body ;  this  in  its  first  state  is  composed  of  a 
layer  of  cells  surrounding  and  enclosing  an  axial  row  of 
cells,  but  by  the  change  of  most  of  the  latter  into  mucilage, 
and  their  consequent  solution,  the  structure  becomes  tubular 
above.  The  lower  cell  of  the  axial  row  is  the  germ-cell  (A, 
Fig.  234 ;  r,  and  e,  e,  e,  Fig.  235) ;  it  is  a  rounded  naked 
mass  of  granular  protoplasm.  In  Anthoceros  the  archego- 
nium  is  very  simple ;  a  row  of  cells  perpendicular  to  the 

surface  of  the 
thallus  becomes 
filled  with  proto- 
plasm ;  the  low- 
er develops  into 
a  germ-cell,  and 
the  others  dis- 
solve, forming 
thus  a  tubular 
opening  to  the 
germ-cell. 

454.  —  After 
fertilization  the 
germ-cell  divides 
successively  in 
several  direc- 
tions, giving  rise 
to  a  tissue,  which 
undergoes  differ- 

Fig.  236.— Anthoceroa  lwi«.     fv.  the  young  eporogonium  ent         modifica- 

cnt  vertically  ;  L.  the  involucre,  winch  is  a  portion  of  the  fj^na    ,»,    tV,Q  ,\\t 

thallus  developed  so  as  to  form  a  kind  of  shenth  ;  c,  c,  tbe  u 

columella  ;  *,  the  spores.     X  150. -After  Hofmeistt-r.  fereilt  orders. but 

which  becomes  in  every  case  asporogonium  (called  in  descrip- 
tive works  a  capsule)  of  some  kind.  In  Eiccia  it  is  a  simple 
globular  case  filled  with  spores  (B,  Fig.  234,  sg]  ;  in  Anthoce- 
ros it  is  an  elongated  body,  with  a  single  circular  layer  of 
spores  (Fig.  236),  while  in  other  cases  its  structure  is  quite 
complex.  In  Marchantia,  the  sporogonium,  when  mature,  is 
a  short-stalked,  rounded  body,  filled  with  spores  and  radially 
placed  thin-walled  cells,  the  elaters,  each  of  which  contains 
one  or  more  spiral  fibres  (7JT.,  Fig.  235,  and  Fig.  240)  ;  it  is 


HEPATIC  JR. 


349 


here  surrounded  by  a  perianth,  a  loose  bag-like  sheath,  which 
grows  up  from  below  the  base  of  the  young  sporogonium,  at 
length  completely  enclosing  it(  VII.  and  VIII. ,  Fig.  235,  pp). 
455. — The  archegonia  of  the  Liverworts  occur  singly,  as 
in  Riccia,  Anthoceros,  etc.,  or  grouped  together,  as  in  Mar- 
cliantia,  Jungermannia,  and  their  allies.  In  Marchantia 
they  grow  in  several  clusters  of  four  to  six  upon  the  under 
surface  of  the  spreading  top  (the  fertile  receptacle)  of  a 
special  branch  of  the  thallus  (Fig.  237).  In  many  cases  the 


FIG.  237. 


FIG.  238. 


Fig.  237.— Fertile  receptacle  of  Marchantia  polynwrpha,  seen  from  below,  st,  its 
stalk,  curiously  grooved  ;  sr,  one  of  the  rays  or  the  star-shaped  receptacle  ;  ./',  one  of 
the  sporogonia  ;  pc,  pc,  perichsetia.  which  surround  several  sporogonia.  X  6.— After 
Sachs. 

Fig.  238. — Plant  of  Plagiochila  asplenioldes,  with  the  bilateral  leafy  axis  below,  p, 
the  perianth  through  whose  top  the  sporogonium  or  capsule  has  pushed  ;  a,  an  un- 
ripe sporogonium  ;  b,  a  ripe  sporogonium  split  open  to  permit  the  escape  of  the  spores. 
—After  Prantl. 

sporogonium  is,  even  when  fully  mature,  sessile,  or  nearly  so, 
there  being  but  a  very  short  stalk  developed ;  but  in  the 
Jungermanniacece,  when  the  sporogonium  is  ripening,  the 
tissue  at  its  base  increases  rapidly,  and  gives  rise  to  a  long 
slender. stalk,  which  pushes  the  spore-case  through  the  dried- 
up  wall  of  the  old  archegonium,  and  raises  it  to  the  height 
often  of  several  centimetres  (Fig.  238). 

456. — There  are  various  ways  in  which  the  spores  are  set 
free  from  the  ripe  sporogonium  or  capsule.     In  Riccia  it 


350 


BOTANY. 


takes  place  simply  by  the  decay  of  the  sporogonium ;  in 
Anthoceros  the  long  sporogonium  splits 
vertically  into  two  long  valves  (Fig. 
239),  while  in  the  greater  part  of  the 
class  it  splits  regularly 
into  a  definite  number 
(four  to  six)  of  recurv- 

ing  segments  ;    in  the 

Fig  239.— Plant  of  An-  latter  the  elaters,  which 

rSr^orogofia^un6  are  present,    doubtless 

opened ;    K,   on  the  left,       •  j        •          Boffina-      4-  V.  a 
Pporogoniaopened.-After    aia       m      Setting      tne 

spores  free.  The  struc- 
ture and  development  of  the  elaters  are 
shown  in  Fig.  240. 

The  following  are  the  principal  orders  of  the 
Hepaticae : 

Order  Ricciaceae.— Consisting  of  terrestrial  or 
aquatic  annual  plants  of  small  size  ;  the  plant- 
body  is  a  dichotomously  branched  thalloid  stem, 
which  bears  a  row  of  scale-like  leaves  upon  the 
under  side.  The  sexual  organs  occur  singly  on  the 
upper  side  of  the  stem,  and  the  sessile,  spherical 
sporogonia  (capsules)  are  immersed  in  it  or  sessile 
upon  it ;  the  capsule  breaks  irregularly  upon  the 
decay  of  its  walls  ;  and  there  are  neither  perianth 
nor  elaters. 

Order    Anthoceroteas.  —  Terrestrial     annual 
plants  with  an  irregularly  branched  thallus.    The 
sexual  organs  are  imbedded  in  the  upper  surface 
of  the  frond,  and  are  of  very  simple  structure  ;  the 
sporogonia  are  long  and  narrow,  and  dehisce  by    of  development.    The 
splitting  into  two  valves  ;  perianth  none  ;  and  the    tobe'a^efon^ate^ell 
elaters,  when  present,  imperfect  and  rudimentary,    with  no  trace ^as^yet 

Order  Marchantiaceae.  —  Terrestrial  perennial 
plants,  with  a  thick,  creeping,  and  dichotomously 
branched  stem,  furnished  beneath  with  numerous 
scale-like  leaves  and  root-hairs  ;  above,  the  stem  is 
provided  with  a  well-developed  epidermis,  and  pe- 
culiar stomata  of  a  complex  structure,  communi-    h™ 
eating  with  lozenge-shaped  cavities  (Figs.  78  and   A,    A,    are     mature 
79,  pp.  91-2).     The  sexual  organs  are  developed  on   fPr°r£s  ulSuSttrt 
special  erect  branches,  and  they  may  occur  on  the    Decaisne. 
same,  or  on  distinct  plants  ;  the  sterile  or  antheridial  branches,  which 


240.— Two   ela- 
different  stages 


are  several  youm; 
right  is  mature.  It 


tions  of  the  wall,  the 


MUSCL  351 

are  sometimes  very  short,  bear  flattened  discs  in  which  the  antheridia 
are  immersed ;  the  fertile  or  archegonial  branches  bear  spreading 
discs,  upon  the  under  side  of  which  the  dependent  archegonia  are  clus- 
tered. The  ripe  sporogonium  (capsule)  is  enclosed  in  a  perianth  ;  it 
opens  by  splitting  part  way  down  from  the  top  into  several  segments, 
and  contains  two-fibred  elaters  mixed  with  the  spores. 

Marchantia  polymorpha,  a  common  species,  is  used  by  quacks  as  a 
medicine. 

M'irchantia  occurs  in  the  Tertiary  (Eocene)  of  Europe,  but  has  not 
been  detected  in  North  America. 

Order  Jungennanniaceae. — Plants  composed  of  a  thallus,  a  thalloid 
stem,  or  a  stem  with  two  or  three  rows  of  leaves  ;  when  there  are  three 
rows  the  third  row  is  on  the  under  side  (constituting  the  amphigastria). 
The  sexual  organs  are  distributed  monoeciously  or  diceciously  ;  in  the 
thalloid  species  they  occur  much  as  in  the  Marchantificece /  in  the 
foliose  forms  the  antheridia  "  are  usually  in  the  axils  of  the  leaves, 
either  singly  or  in  groups,"  and  the  archegonia  are  most  frequently 
clustered  upon  the  summits  of  the  shoots,  and  are  generally  concealed 
by  the  leaves.  The  ripe  sporogonium  (capsule),  which  is  usually  long 
stalked,  opens  by  splitting  into  four  parts  from  the  apex  to  the  base  ; 
it  contains  one-  or  two-fibred  elaters  mixed  with  the  spores.  Many 
species  are  common  on  rocks  and  the  bark  of  trees. 

The  modern  genera  Jungermannia,  Frvllania,  and  L'jeunia,  were 
represented  in  the  Tertiary  (Miocene). 

§  II.  CLASS  Musci. 

457. — The  adult  plant-body  in  this  class,  which  includes, 
besides  the  Sphagnums,  all  the  true  Mosses,  is  always  a  leafy 
stem,  which  is  rarely  bilateral.  It  is  fixed  to  the  soil  or  other 
substratum  by  means  of  articulated  root-hairs,  or  rhizoids, 
which  grow  out  from  the  sides  of  the  stem.  The  leaves  are 
sessile,  usually  composed  of  a  single  layer  of  cells,  and  either 
nerveless,  or  traversed  longitudinally  by  a  single  rib,  rarely 
by  two  ;  they  are  arranged  in  two  or  three  straight  or  spiral 
rows,  and  are  usually  inserted  more  or  less  obliquely  to  the 
stem. 

458. — The  tissues  of  the  Mosses  present  a  considerable 
advance"  upon  those  of  the  Liverworts.  In  the  stem  there  is 
usually  a  considerable  thickening  of  the  outer  layer,  or  layers, 
of  cells,  constituting  a  kind  of  imperfect  sclerenchyma.  In 
some  cases  (Leucobryum,  Barbida,  etc.)  the  remainder  of 
the  stem  is  composed  of  thin- walled  tissue  (parenchyma), 


352  BOTANY. 

but  in  others  (Funaria,  Mnium,  Bryum,  etc.)  there  is  an 
axial  bundle  of  very  narrow  thin-walled-cells  ;  in  still  others 
(Atrichum,  Polytriehwn,  etc.)  the  cells  of  the  central  bundle 
are  considerably  thickened,  and  in  the  last-named  genus 
there  are  extra-axial  bundles.  In  a  few  cases  there  have 
been  observed  bundles  of  thin-walled  cells  extending  from 
the  leaves  obliquely  through  the  tissues  of  the  stem  to  the 
central  bundle.  From  the  foregoing  statements  it  cannot 
be  doubted  that  the  Mosses  possess  rudimentary  fibro-vascu- 
lar  bundles.  Stomata  resembling  those  of  the  higher  plants 
occur  on  the  capsules  ;  they  are  not  found  upon  the  leaves 
or  stems.  The  stem  always  grows  from  an  apical  cell. 

450. — Mosses  are,  for  the  most  part,  aerial  plants,  growing 
upon  moist  earth  or  rocks,  or  even  upon  the  sides  of  trees, 
a  comparatively  small  number  of  species  being  aquatic  ;  they 
range  in  size  from  less  than  a  millimetre  to  many  centimetres 
in  length,  the  most  common  height  being  from  two  to  four 
centimetres.  They  are  all  chlorophyll-bearing  plants,  and  are 
generally  of  a  bright  green  color  ;  occasionally,  however,  they 
are  whitish  or  brownish. 

460. — The  sexual  organs  of  Mosses  consist  of  antheridia 
and  archegonia ;  they  are  usually  found  upon  the  end  of  the 
leafy  axis,  and  generally  occur  in  considerable  numbers. 
Most  of  the  species  are  either  monoecious  or  dioecious,  while 
some  are  hermaphrodite.  There  is,  however,  but  little  value 
to  be  attached  to  the  kind  of  inflorescence,  as  it  is  often  dif- 
ferent in  genera  which  are  certainly  near  allies.  Even  in 
the  same  genus  some  of  the  species  may  be  dioecious,  while 
others  are  monoecious  or  hermaphrodite  ;  and  occasionally,  as 
in  the  genus  Bryum,  the  three  kinds  of  inflorescence  are 
found  ;  rarely  a  species  is  itself  variable  in  this  respect — 
e.g.,  Bryum  crudum,  which  is  mostly  hermaphrodite,  but 
sometimes  dioecious. 

461. — The  antheridia  are  generally  club-shaped,  stalked 
bodies  (spherical  in  Sphagnacece),  with  a  wall  composed  of  a 
single  layer  of  cells  enclosing  a  mass  of  sperm-cells,  each  of 
which  contains  a  bi-ciliate,  spirally  coiled,  thread-shaped  sper- 
matozoid  (Fig.  242,  B}.  When  the  antheridium  is  mature  its 
wall  ruptures  when  wet,  and  the  sperm-cells  escape  in  a  mass 


MU8CI. 


353 


of  mucilage  ;  the  walls  of  the  sperm-cells  break,  and  the 
spermatozoids  are  set  free  (Fig.  242).  The  antheridia  are 
frequently  intermingled  with  variously  shaped  hairs  (para- 
physes),  and  about  the  cluster  there  may  be  one  or  more 


FIG.  241.  Fi0.  242. 

Fig.  241. — Female  reproductive  organs  of  a  moss,  Funaria  liygrmmtrica.  A  apex 
of  the  stem  ;  a,  archegonia  ;  6,  leaves.  £,  archegoniam ;  b.  base  ;  A,  neck  ;  m 
mouth.  C\  month  of  fertilized  archegonium.  A  x  100,  B  X  550  —After  Sachs. 

Fiir.  242. — Male  reproductive  organs  of  the  same  moss.  A,  antheridium  open  and 
prrmiiting  the  spermatozoids  a  to  escape.  B,  6.  sperm-cell  of  another  moss  (Polu- 
trtc/i/ini),  with  contained  spermatoaotd;  c,  spermatozoid  free,  with  two  cells  at  the 
pointed  extremity.  A  x  350,  B  x  800.— After  Sachs. 

whorls  of  leaves  or  bracts,  giving  to  the  whole  much  of  the 
appearance  of  a  flower  of  the  Phanerogams. 

462. — The  archegonia  are  elongated  flask-shaped  bodies, 
with  a  swelling  base,  and  a  long,  slender  neck  (Fig.  241, 
B).  The  wall  is  composed  of  a  single  layer  of  cells,  except 


354 


BOTANT. 


below,  where  there  are  two  layers.  The  neck  of  the  arche- 
gonium  at  first  contains  an  axial  row  of  cells,  but  these 
become  dissolved  and  transformed  into  a  mucilaginous  mass 

just  before  the  time  of 
fertilization.  The  germ- 
cell  lies  in  the  lower 
swollen  portion  of  the  ar- 
chegonium  ;  it  consists  of 
a  naked  rounded  mass  of 
protoplasm.  At  the  time 
of  fertilization  the  upper- 
most cells  of  the  neck  of 
the  archegonium  diverge 
from  one  another,  and 
thus  form  an  open  chan- 
nel to  the  germ-cell. 

463. — Fertilization 
takes  place  in  the  water, 
or  in  the  presence  of  a 
considerable  amount  of 
moisture.  The  spermato- 
zoids,  which  are  produced 
in  great  numbers,  move 
through  the  water  by 
means  of  their  vibratile 
cilia,  and  some  of  them 
find  their  way  down  the 
channels  of  the  archego- 

Fte.  m-Developtnent  of  the  snorogonium    nia>  where  tnCJ  Ullit°  thcir 

otlfaHahwromttrtca    A  longitudinal  sec-  substance  Avith  the  eerm- 

tion  of  the  archegonium,  b,  b,  shortly  after  fer- 
tilization ;  h,  neck  ; /,  iipioil  portion  of  young  cells.       As  a  result  Ol    this 
sporogonium;  f,  basal  portion  of  young  sporo- 

goniiim.    5,  vertical  section  of  a  female  flower;  Union,  the   germ-Cell    SU1'- 

/',  young  sporoiroiiium  elongating,  and carrving  ,       .,      ,»        .,,                  .. 

up  the  remains  of  the  old  arclu-goninm,  c  (now  I'OUllds    itself    Wltll    a  Wall 

called  tlie  calyptru)  ;  h,  neck  of  old  archego-  <•       11    i                   i 

nium.    6',  a  later  btuge  of  the  sa.nc.    Invalid  of  Cellulose,  and  SOOU   Ull- 

C  the  sporogonia  are  seen  to  he  growing  down-  flovrrrin-,  /livicion  in  viriona 

ward  into  the  tissues  of  the  leafy  stem     A  X  tlGlgOCb  dl\  1S1O1L  111  A  dl  1OU8 

600 ;  B  and  c much  less.-After  Sachs.  directions,  giving  rise  to  a 

many-celled  mass,  the  young  sporogonium  (/,  /',  Fig.  243, 
A).  In  most  Mosses  the  young  sporogonium  elongates  rap- 
idly, and  while  its  upper  end  carries  up  the  remains  of 


MUSGI. 


355 


the  old  archegonium  (h,  Fig.  243,  B  and  C),  the  lower  end 
penetrates  into  the  tissues  of  the  leafy  axis  ;  the  upper  end 
develops  into  a  spore-case,  while  the  remainder  becomes  a 
filiform  stalk  (seta)  of  greater 
or  less  length.  In  the  Sphag- 
nacece,  however,  the  sporogo- 
nium  does  not  greatly  elongate, 
but,  on  the  contrary,  remains 
quite  short,  while  the  end  of 
the  leafy  axis,  soon  after  the  fer- 
tilization of  the  archegonium, 
elongates  into  a  slender  leafless 
stalk  (pseudopodium},  which 
carries  up  the  developing  sporo- 
gonium  upon  its  upper  expand- 
ed end  (v,  ps,  Fig.  244,  B  and 
C).  Essentially  the  same 
structure  is  found  in  Andrce- 
acecB  and  Phascacece. 

464.  —  The  ripe  sporogo- 
nium  (capsule,  theca,  or  spore- 
case)  is  of  various  shapes,  but 
generally  more  or  less  cylindri- 
cal or  globose  ;  it  differs  much 
in  its  particular  structure  in 
the  different  orders,  but  in  all  F'g-  244.— Development  of  the  sporo- 

gonium  of  Sphaimmn   aatOtfoHttm.    A, 

Certain    internal     Cells    become   longitudinal  section  of  a  f,-male  flower; 

.,  ,,  i  •    i       j-      ar>  archegonla ;   c/i.  voiini;  pericha'tial 

Spore    mother-Cells,    Which     dl-   leaves ;    y,  upper  leaves  of    the  shoot 

vide  into  four  daughter-cells,  SttSJni  VTu 


the  spores.    The  capsule,  when  & 

ripe,  opens  by  the  falling  off  of  S 

a     terminal    lid    (opercnlum)  *™  e 

(SpllCUinacece  and  Briiacece),  Or  curved  row  of  epore  mother-cells.     (7, 

.  ,  ,  T,    •  Sphagnum  nquarros'im.    sg,  ripe  sporo- 

111  a  few  Cases   by  Splitting  ver-  goninm;  a,  operculum;  c,  torn  calyp- 

,t      11         /   A      7       '  \          •        ,i  tra ;    gs,  the  elongated  pceudopodium ; 

tically  (Andrcvacece}  ;  in  the  ,*. p.-ftchietiai leaves.  In ma|iifled.- 
amaU  order  Phascacece  the  cap-  Al 

sule  is  indehiscent,  and  the  spores  are  set  free  only  by  its 
decay  or  irregular  rupture.  The  ripe  spores  are  roundish 
or  more  or  less  angled,  and  have  a  roughened  or  granulated 


356 


BOTANY. 


exospore,  which  is  generally  yellow  in  color.  Internally 
the  spores  contain,  in  addition  to  the  protoplasm,  oil-drops 
and  chlorophyll  granules. 

465. — In  the  germination  of  the  spores,  the  exospore  is 
ruptured,  and  the  endospore  protrudes  as  a  tubular  filament, 
which  elongates  by  the  continued  growth  of  an  apical  cell ; 
partitions  form  at  close  intervals,  and  the  threads  branch 
freely,  giving  rise  to  a  green  Conferva-like  mass,  the  pro- 
tonema  (Fig.  245,  B}.  In  the  Sphagnacece,  however,  the 
protonema  is  a  flattened  mass,  somewhat  like  the  plant-body 


Fig.  246. — Development  of  Funaria  hygrometrica.  A,  germinating  spores  ;  «,  rnp- 
tnred  exospore  ;  rv,  w,  young  root  hairs— on  the  oppoi-ite  side  of  the  spore  is  the 
beginning  of  the  protonema  ;  f,  vacuole  in  a  germinating  spore.  £,  port  of  a  proto- 
nema three  weeks  after  germination  ;  h,  a  primary  shoot  with  brown  walls— from  it 
arise  several  lateral  branches  b.  K,  a  young  bud  or  rudiment  of  a  leaf-bearing 
axis  ;  M>,  a  small  root  hair.  .1  X  550  ;  £  X  TO. — After  Sachs. 

of  the  lower  Liverworts.  After  a  greater  or  less  period  of 
vegetation,  there  arise  upon  the  protonema  small  buds,  which 
develop  into  leaf-bearing  axes  (Fig.  245,  B,  K}.  These  buds 
originate  from  single  cells,  which  repeatedly  divide  them- 
selves by  diagonal  partitions  ;  the  apical  cell  thus  formed 
in  each  case  becomes  the  apical  cell  of  the  bud,  and  the 
new  axis.  The  leafy  axes  thus  formed  sooner  or  later  bear 
the  sexual  organs,  thus  completing  the  round  of  life. 

466. — Mosses  reproduce  themselves  asexnally,  sometimes 
iu  a  manner  quite  similar  to  that  of  the  Liverworts— c.y.,  in 


SPHAGNACE^E.  357 

Tetraphis  pellucida,  where  the  leafy  axis  frequently  bears 
a  terminal  cup-shaped  receptacle,  containing  many  lenti- 
form  stalked  gemmae  ;  these  separate  spontaneously,  and 
give  rise  to  a  kind  of  protonerna,  and  upon  this  buds  after- 
ward arise,  from  which  leafy  axes  are  developed.  Many 
Mosses  reproduce  themselves  by  the  formation  of  a  pro- 
tonema  from  the  leaves  and  the  root-hairs,  and  from  buds 
formed  upon  such  a  protonema  new  plants  may  arise.  Even 
the  protonema  is  capable  of  an  asexual  reproduction  of  itself  ; 
sometimes  its  individual  cells  become  rounded,  spontane- 
ously separate  themselves,  become  thicker  walled,  and  then 
remain  inactive  for  a  time ;  they  thus  remind  one  of  the 
conidia  of  some  Thallophytes. 

There  are  four  well-marked  orders  of  Mosses,  as  follows  : 

Order  Sphagnaceas. — The  plants  of  this  order  are  large,  soft,  and 
usually  pale  colored ;  they  inhabit  bogs  and  swampy  places,  and  are 
known  as  the  Peat  Mosses.  The  protonema  is  a  flat  thallus,  or  com- 
posed of  branched  filaments,  accordingly  as  it  has  developed  upon  a 
solid  substratum  or  in  water  ;  the  leafy  axis  is  usually  much  elongated, 
and  as  it  dies  away  below  it  grows  at  the  summit ;  the  leaves  are  usu- 
ally five-ranked,  and  are  composed  of  two  kinds  of  tissue,  viz.,  (1)  one 
made  up  of  small  chlorophyll-bearing  cells,  and  (2)  one  made  up  of 
large  perforated  cells  ;  the  latter  are  usually  filled  with  water,  and  to 
them  is  due  the  well-known  power  possessed  by  the  Peat  Mosses,  of 
retaining  moisture  for  a  great  length  of  time .  Root-hairs  (rhizoids)  are 
present  only  in  young  plants,  their  place  being  taken  by  the  reflexed 
branches,  which  are  always  abundant. 

The  inflorescence  is  monoecious  or  dioecious ;  the  rounded  (almost 
spherical)  antheridia  occur  singly  by  the  sides  of  the  leaves  of  catkin- 
like  branches  (not  axillary,  as  stated  in  some  books) ;  the  archegonia 
are  developed  upon  the  ends  of  certain  branches  (A,  Fig.  244).  The 
ripe  sporogonium  (capsule  or  spore-case)  is  globose,  or  nearly  so  ;  its  seta 
is  short,  but  it  is  borne  upon  a  more  or  less  elongated  pseudopodium, 
which  resembles  a  seta.  The  old  archegonium  (calyptra)  is  ruptured 
irregularly  by  the  growing  sporogonium,  and  forms  only  a  very  imper- 
fect cap  to  the  spore-case.  In  the  development  of  the  spores  the  cells  of 
a  layer  parallel  to  the  surface  of  the  upper  half  of  the  capsule  become 
modified  as  spore  mother-cells  (B,  Fig.  244).  At  maturity  a  circular 
portion  of  the  apex  of  the  capsule  spontaneously  separates  as  a  lid 
(operculum),  and  allows  the  spores  to  escape  (C,  Fig.  244,  d). 

The  order  contains  but  a  single  genus,  Sphagnum,  represented  in 
the  United  States  by  twenty  or  more  species.  These  are  of  some  eco- 
nomic account,  as  they  furnish  a  most  excellent  material  for  "  packing  " 
in  the  transportation  of  living  plants. 


358 


BOTANY. 


The  genus  Sphagnum  was  represented  in  the  Tertiary  (Miocene)  of 
Europe. 

Order  Andreeacese.—  In  this  small  order  the  little  plants  of  which 
it  is  composed  have  a  short-stalked  sporogonium,  raised  upon  a  pseudo- 
podium,  as  in  the  Sphagnacece  ;  the  sporogonium  contains  a  layer  of 
spore-forming  tissue,  disposed  as  in  the  preceding  order  ;  but  the  ripe 
capsule  opens  by  splitting  into  four  longitudinal  valves,  in  this  remind- 
ing one  of  the  Jungermanniaceoe.  In  the  growth  of  the  sporogouium 
the  old  archegoniuui  is  torn  away  at  its  base,  and  carried  up  as  a  cap 
(calyptra),  which  covers  the  apex  of 
the  capsule. 

The  principal  genus  is  Andrcea, 
represented  in  the  United  States  by 
a  few  alpine  or  sub-alpine  species  of 
brownish  or  blackish  rock  -  loving 
Mosses. 

Order  Phascacese.—  These  small 
Mosses  are  peculiar  in  having  but 
a  little  development  of  leafy  axis,  and 
in  their  persistent  protonema.  The 
sporogonium  is  short-stalked,  or  ses- 
sile, and  the  pseudopodium  is  very 
short,  or  entirely  wanting.  The 
spores  are,  in  the  simplest  genus  (Ar- 
chidium),  developed  from  a  single 
mother-cell,  while  in  the  higher  ones 
they  develop  from  a  layer  of  mother- 

.       ,  °f8'    mucb   as  .in,  ^    next    °/df' 
a  young  leafy  plant,  g,  with  sporogo-  The  capsule  is  indelnscent,  and  the 

^£aV^  "l*>«»  are  set  free  only  by  its  decay. 
c,  thecalypira;   «.  seta.  The    old  archegonium  persists  as   a 

^Stt^K  cal^tra  «™rin*  the  capsule. 
which  will  separate  from  the  remainder       The  principal  genera   are  Archidi- 
of  the  capsule  at  a;  »,  peristomc-  ;  «,  n,  i    r>       ?  •          mi 

spore-bearing  layer  ;  i,  air  cavity  inr-  «™,    PkiKum,   and  Bniefna.       The 
rounding  the  columella,  and  crossed  by  species  are  terrestrial,  and  many  are 
confervoid  filaments  ;   t,   inferior  con-    r         . 
n  -ctionof  the  columella  with  the  tissues  annuals. 


Sachs.  rope  a  fossil  species  of  fhatcum  has 

been  found. 

Order  Bryaoese.  —  The  plants  of  this  order  constitute  the  true 
Mosses.  They  are  usually  bright  green  (in  a  few  genera  brownish), 
and  in  the  great  majority  of  instances  live  upon  moist  ground  and 
rocks,  or  upon  the  bark  of  trees  ;  in  a  comparatively  small  number 
of  cases  the  species  live  in  the  water. 

In  the  development  of  their  tissues  and  the  complex  structure  of 
their  sporogonia  the  Bryacear  clearly  stand  at  the  head  of  the  Bryo- 
phyte  Division.  The  tissues,  as  indicated  above  (paragraph  458),  attain 


BRYACE^E. 


359 


247.— Two  capsules 
urn  argertteum.  The 
•  left  is  still  per- 


or-        t      t       apez  ishown 
ain    the  lid  or  operculnm;  the 


in  some  cases  a  development  which  foreshadows  the  differentiation  of 
the  stem  into  the  epidermal,  fibro-vascular,  and  fundamental  systems  of 
the  higher  plants.  In  Polytrichum,  for  example,  there  can  be  no  doubt 
that  the  axial  and  extra-axial  bundlesof  elongated  cells  with  thickened 
walls  found  in  the  stem  represent  the  fibro-vascular  bundles  of  the 
Pteridophytes  and  Phanerogams  ;  the  bundles 
of  elongated  thin-walled  cells  which  pass 
downward  through  the  stem  from  the  base  of 
the  leaf,  in  Splachnum,  must  also  be  regarded 
as  representing  rudimentary  foliar  bundles. 

While  these  higher  Mosses  cannot  properly 
be  classed  with  vascular  plants,  their  tissues 
in  some  cases  reach  so  high  a  development  as 
to  show  that  there  is  no  abrupt  change  in  pass- 
ing from  the  so-called  non-vascular  plants  to 
the  vascular  ones. 

The  inflorescence  of  Bryaceae  is  hermaphro- 
dite,  monoecious,  or  dioecious.  The  sexual  or- 

gans   are  situated  on  the   apex   of  the   mai 

s          .    ,      .,          ,  ,         ,        one  on  the  right  baa  dropped 
stem  (Acrocarpae),  or  of  short  lateral  branches    jt8  opurculum,  exposing  the 

(Pleurocarpse).  The  sporogonium,  in  its  de-  ggB*™£  Ma^ed"^6" 
velopment,  carries  up  the  old  archegonium  as 

a  calyptra,  which  quickly  falls  away  in  some  genera  (e.g.,  Bryum, 
Bartramia,  etc.),  while  in  others  (e.g.,  Polytrichum,  Pogonatum,  etc.)  it 
persists  as  a  closely  fitting  covering  of  the  capsule  ;  between  these 
two  extremes  there  are  all  gradations. 

The  sporogonium  is  usually  long  stalked  (Fig. 
246,  B).  The  capsule  is  generally  more  or  less 
ovoid  or  cylindrical.  It  is  at  first  composed  of  pa- 
renchymatous  tissue,  which  entirely  fills  up  its 
interior;  as  it  enlarges,  however,  an  annular  in- 
tercellular air  cavity  forms,  separating  a  cylin- 
drical axial  portion  from  the  outer  portion,  which 
forms  the  wall  of  the  capsule.  The  axial  cylin- 
der remains  in  connection  with  the  remainder 
—  °^  ^ie  caPau^e  at  its  top  and  bottom  (£,  Fig.  246, 

art  of  the  capsule  of    0),  and   it  is,  moreover,  slightly  connected  with 
^sfowiSfTC    the  capsule  walls  by  chlorophyll-bearing  confer- 
double  peristome.  The    void  filaments,  which  pass  across  the  air  cavity. 
of^L^^the  inner  'of    ^he  rather  dense  tissues  below  and  surrounding 
cilia.   Magnified.  the  air  cavity  in  the  immature  capsule  are  com- 

posed of  chlorophyll-bearing  cells,  and  the  epidermis  covering  these 
portions  is  supplied  with  stomata.  The  spores  are  developed  from  a 
layer  of  cells  (the  third  or  fourth  from  the  outside)  in  the  axial  cylinder 
(s,  Fig.  246,  (7)  ;  and  each  cell  of  the  spore-bearing  layer  produces  four 
spores.  The  portion  of  the  axial  cylinder  within  the  spore-bearing 


248—  A    ical 


360  BOTANY. 

layer  is  called  the  columella  (e,  c',  Fig.  246,  C),  while  the  two  or  three 
layers  of  cells  exterior  to  it  constitute  the  spore-sac. 

In  all  the  members  of  this  order,  the  capsule,  when  ripe,  opens  by  the 
falling  away  of  a  lid  (operculum),  which  is  composed  for  the  most  part 
of  the  epidermis  covering  the  apical  portion  (Fig.  247).  In  most  of  the 
genera,  when  the  operculum  falls  off,  one  or  two  rows  of  teeth  (the 
peristome)  are  exposed,  surrounding  the  opening  of  the  capsule  (Fig. 
248).  These  teeth,  which  are  always  some  multiple  of  four  (4,  8,  16, 
32,  or  64),  are  in  most  cases  formed  respectively  of  the  thickened  outer 
and  inner  walls  6f  rows  of  cells  which  lie  beneath  and  parallel  to  the 
wall  of  the  operculum ,  and  converge  toward  its  centre.  Each  tooth 
is  thus  made  up  of  parts  of  several  cells,  and  the  transverse  lines  seen 
upon  it  are  the  thickened  transverse  walls  which  formerly  separated 
the  original  cell  cavities. 

The  peristome  of  Polytrichum  and  its  allies  is  composed  of  bundles 
of  thickened  cells,  hence  they  are  much  firmer  than  in  those  genera  in 
which  they  are  made  of  fragments  of  cell  membranes. 

The  Bryacese  include  many  genera,  which  are  widely  distributed 
throughout  the  world.  The  genera  arrange  themselves  under  two 
groups  (sub-orders),  according  as  the  sporogonia  are  terminal  or 
lateral,  with  reference  to  the  main  axis  ;  the  first  constitute  the  Aero- 
carpce,  including  Funaria,  Bryum,  Mnium,  Polytrichum,  etc.  ;  those 
with  lateral  sporogonia  constitute  the  Pleurocarpce,  and  include  Fonti- 
nalis,  Climacium,  Hypnum,  etc. 

In  the  Tertiary  of  Europe  the  order  is  represented  by  an  Eocene  spe- 
cies of  Musettes,  and  Miocene  species  of  the  modern  genera  Fontincdis, 
Dicranum,  Barbvla,  Polytrichum,  Hypnum,  etc.  A  single  species  of 
Hypnum  from  the  Tertiary  of  Colorado  is  the  only  American  fossil  of 
this  order  yet  detected. 


The  most  valuable  systematic  works  for  the  student  of  the  Bryo- 
phytes  of  this  country  are  "  Musci  and  Hepaticse  of  the  Eastern  United 
States,"  by  W.  S.  Sullivant,  1871;  "  Icones  Muscorum,"  by  the  same 
author,  1864-74  ;  and  "  Catalogue  of  Pacific  Coast  Mosses,"  by  L.  Les- 
quereux,  1868. 


CHAPTER    XIX. 

PTERIDOPHYTA. 

467. — The  plants  of  this  Division  constitute  the  so-called 
Vascular  Cryptogams.  They  present  an  alternation  of  sexual 
and  asexual  generations,  much  as  in  the  Byrf>phytes,  but  in 
the  higher  orders  it  shows  signs  of  disappearing.  The  first 
generation  proceeds  directly  from  the  germination  of  the 
spore  ;  it  is  made  up  of  simple  tissues,  and  is  usually  short- 
lived ;  it  bears  the  sexual  organs,  and  hence  is  called  the 
sexual  generation.  The  second  generation,  which  results 
from  the  fertilization  of  a  germ-cell  developed  upon  the 
preceding  one,  is  long-lived,  and  made  up  in  most  cases 
of  tissues  of  a  high  order,  and  the  plant-body  is  differen- 
tiated into  root,  stem,  and  leaves  ;  upon  this  second  genera- 
tion spores  arise  asexually  year  after  year,  and  from  these 
spores  the  sexual  generation  is  again  produced. 

468. — The  sexual  generation,  called  the  Prothallium,  is 
generally  a  flattened  thallus-like  growth,  somewhat  resem- 
bling the  plant-body  of  the  lower  Bryophytes.  It  is  always 
small,  and  composed  throughout  of  parenchyma  disposed  in 
one,  or  at  most  a  few  layers  ;  on  its  under  surface  it  generally 
produces  root-hairs  (rhizoids),  which  serve  to  fix  it  to  the 
ground,  and  doubtless  also  serve  as  organs  of  nutrition. 
The  cells  of  the  prothallium  are  in  most  cases  richly  sup- 
plied with  chlorophyll,  by  means  of  which  they  elaborate 
material  for  its  growth. 

469. — When  the  prothallia  have  become  sufficiently  large, 
they  develop  the  sexual  organs,  the  antheridia  and  arche- 
gonia.  These  are  formed  in  essentially  the  same  manner  as 
they  are  in  the  two  lower  orders  of  Hepaticae  (Ricciacece  and 
Anthocerotea).  They  are  more  or  less  imbedded  in  the  sur- 


362  BOTANY. 

face  of  the  prothallium,  and  consist  of  masses  of  cells,  enclos- 
ing in  each  case  a  single  cell,  which  develops  into  one  germ- 
cell  (in  the  archegonia),  or  a  number  of  sperm-cells  (in  the 
antheridia).  The  sperm-cells  produce  spirally  coiled  sperma- 
tozoids,  which  fertilize  the  germ-cell  by  passing  down  the 
canal  in  the  neck  of  each  archegonium.  In  many  of  the 
plants  of  this  division  there  is  a  strong  tendency  toward 
diceciousness  in  the  prothallia,  and  in  the  higher  genera  it 
becomes  the  invariable  rule. 

470. — The  result  of  fertilization  is  the  formation  of  a 
young  plant,  by  the  growth  and  successive  division  of  the 
fertilized  cell.  In  its  first  stages  the  new  plant  is  usually 
quite  simple,  but  it  soon  becomes,  in  the  greater  part  of  the 
Division,  a  leafy  plant  with  highly  developed  tissues.  After 
a  greater  or  less  period  of  vegetation  the  new  plant  produces 
spores  by  the  internal  cell-division  of  certain  mother-cells, 
each  of  the  latter  producing  four  spores.  The  particular 
structure  of  the  spore-bearing  organs  and  the  place  of  their 
appearance  are  quite  different  in  the  different  classes.  In 
many  cases  they  are  produced  upon  the  surface  of  the 
ordinary  green  leaves,  in  other  cases  upon  modified  leaves, 
while  in  still  others  upon  the  bases  of  the  leaves,  in  their 
axils.  The  spores  are  in  most  cases  of  one  kind,  but  in 
certain  genera  there  are  large  spores  (macrospores),  and  small 
ones  (microspores). 

471. — True  roots  first  make  their  appearance  in  this 
division.  A  root  is  developed  upon  the  young  plant,  but 
this  never  attains  a  great  size,  and  others  form  in  acropetal 
order  upon  the  stem,  and  even  occasionally  upon  the  leaves. 

472. — In  the  Pteridophytes  the  three  tissue  systems — epi- 
dermal, fibro-vascular,  and  fundamental — attain  a  good  de- 
gree of  development.  The  epidermis  is  distinct,  and  con- 
tains stomata  similar  in  form  and  position  to  those  of  the 
Phanerogams.  In  many  cases  there  is  a  strong  development 
of  trichomes,  as  in  the  Ferns,  where  the  young  leaves  are 
usually  densely  covered  with  scurfy  hairs.  The  fibro-vascu- 
lar bundles  are  always  closed,  and  generally  are  what  De 
Bary  calls  concentric  bundles;  in  the  Equisetinge,  however, 
collateral  bundles  occur,  and  in  Lycopodinae  radial  bundles. 


EQUISETINJE.  363 

The  bundles  vary  considerably  as  to  the  tissues  they  contain, 
but  they  generally  possess  tracheary  and  sieve  tissues  ;  the 
former  is  usually  well-developed  as  spiral,  scalariform,  or 
pitted.  Sieve  tissue  is,  as  a  rule,  not  so  well  developed  as 
the  former,  consisting  for  the  most  part  of  thin-walled, 
elongated  cells,  in  Avhich  the  characteristic  sieves  are  less 
regularly  formed.  Fibrous  tissue  occurs  only  to  a  limited 
extent  as  a  constituent  of  the  fibro- vascular  bundles.  Paren- 
chyma is  also  found  in  them,  but,  like  the  former,  it  is 
usually  not  abundant.  The  fundamental  system  of  tissues 
includes  various  forms  of  parenchyma  and  sclerenchyma  ; 
the  latter,  however,  is  frequently  wanting.  Collenchyma  and 
laticiferous  tissue  are  not  found  in  the  greater  part  of  the 
Division  ;  but  the  former  occurs  in  Marattiaceae,  in  which  or- 
der, according  to  Sachs'  observations,  there  are  also  indica- 
tions of  a  rudimentary  laticiferous  tissue. 

§  I.    CLASS  EQUISETIK^E. 

473. — In  the  plants  of  this  class  the  plant-body  (of  the 
asexual  generation)  consists  of  a  hollow  elongated  and  jointed 
axis,  bearing  upon  each  node  a  whorl  of  narrow  united  leaves, 
which  form  a  close  sheath  (s,  Fig.  249)  ;  the  stem  is  always 
grooved  or  striate,  and  is  usually  rough  and  hard  from  the 
large  amount  of  silica  deposited  in  the  epidermis.  The 
branches  arise  in  the  axils  of  the  leaves  constituting  the 
sheaths,  and  consequently  they  are  verticillate,  or  in  whorls. 
Both  the  main  axis  and  the  branches  are  in  most  cases  richly 
supplied  with  chlorophyll-bearing  parenchyma ;  in  some  of 
the  species  (e.g.,  Equisetum  Telmateia  and  E.  arvense)  the 
stems  which  bear  the  spores  are  destitute  of  chlorophyll. 
All  the  species  develop  numerous  colorless  branching  under- 
ground stems,  which  bear  roots  and  rudimentary  sheaths, 
and  which  each  year  send  up  the  vegetating  and  spore- 
bearing  stems.  Both  root  and  stem  grow  from  an  apical  cell. 

474. — In  common  with  most  members  of  this  division, 
the  Equisetinae  are  perennial  plants.  In  some  species  the 
underground  portions  only  persist,  the  aerial  stems  dying  at 
the  end  of  each  year,  as  is  the  case  in  E.  Telmateia,  E.  arvensef 


384 


BOTANY. 


E.  sylvaticum,  E.  limosum,  and  some  other  species.  In 
other  species,  as  E.  hyemak,  E.  Icevigatum,  the  aerial  steins 
also  persist ;  the  latter  are  hence  known  as  perennial- 
stemmed. 

475. — The  prothallia  are  irregularly  branched  thallus-like 
growths,  composed  of  chlorophyll-bearing  parenchymatous 
cells  arranged  in  one  or  more  layers.  Upon  the  under  side 
they  bear  root-hairs,  which  fix  them  to  the  ground.  They 
are  usually  small  in  size,  ranging  from  two  or  three  to  ten  or 
twelve  mm.  in  length.  In  most  species  the  prothallia  are 
dioecious,  bearing  but  one  kind  of 
sexual  organ  upon  each,  and  in  such 
cases  it  always  happens  that  those 
which  bear  the  antheridia  are  much 
smaller  than  those  which  bear  arche- 
gonia.  Both  kinds  live  but  for  a 
short  time,  the  whole  period  of  their 
existence  usually  not  extending  be- 
yond a  few  months  ;  the  male  pro- 
thallia appear  to  endure  for  a  some- 
what shorter  period  than  those  which 
bear  archegonia. 

476. — The  antheridia  occur  upon 
the  ends  or  margins  of  the  prothal- 
lia ;    they  arise  from   the  repeated 
nea  leaves  ;2,the,rseP.   diviaionof     a    marginal   cell,    thus 
apices  (teeth) ;  a,  a',  a",   forming  an  inner  mass  of  cells  rich 

mternodes     of     lateral    .  ,  ,  , 

in  protoplasm,  and  a  covering  layer 
(an1,  Fig.  250,  A).  By  the  continued  division  of  the  inner 
cells  100  to  150  cubical  cells  are  formed,  each  of  which  con- 
tains a  single  sperm-cell ;  somewhat  later  the  walls  of  the 
cubical  cells  dissolve,  and  the  sperm-cells  become  free  in  the 
antheridial  cavity,  from  which  they  are  soon  allowed  to  es- 
cape by  the  separation  of  the  apical  cells  of  the  enveloping 
layer  (an,  Fig.  250,  A}.  At  this  time  each  sperm-cell  con- 
tains a  spermatozoid,  which  soon  escapes  by  the  rupture  of 
the  cell-wall.  Each  spermatozoid  is  a  thick,  spirally  coiled 
filament  of  protoplasm,  tapering  anteriorly,  where  it  is  pro- 
vided with  numerous  cilia,  which  give  it  motility. 


right  stem  of  Equisetum  Tel- 
mateia  (nat.  size),  i,  i,  inter- 
nodes  ;  A,  central  hollow  space 
of  internode  ;  /,  air  spaces  (la- 
ci  111:1  •  i  in  the  cortex ;  #,  sheath 
of  united  leaves  ;  z,  their  se 
arate 
basal 
branches.— After  Sachs. 


365 


477. — The  archegonia  arise  upon  the  anterior  edge  of  the 
prothallium,  from  the  division  of  single  cells.  The  mother- 
cell  of  the  archegonium  undergoes  several  divisions,  result- 
ing in  the  formation  of  a  germ-cell,  surrounded  by  one  or 
more  layers  of  cells.  The  germ-cell  lies  at  a  considerable 
depth  beneath  the  general  surface  of  the  prothallium,  above 


Fig.  250.—  A,  fragment  of  a  prothallium  of  Equisetum  limosum  (in  the  middle  of 
'y);   a,  an  apical  cell  of  a  growing  point ;  an,  a  ripe  antheridium,  with  escaping 
sperm-cells;  aw',  a  young  antheridium.    ^.longitudinal  section  of  an  archegonium 


July) 


of  Equisetum  arrente,  immediately  after  the  opening  of  its  apex,  showing  the  germ- 
cell  in  the  cavity  below,  surrounded  hy  the  parenchyma  of  thej>rothallium.  C,  longi- 
tudinal section  of  the  germ-cell,  or  rudimentary  embryo,  of  E.  arveme,  shortly  after 
fertilization  ;  it  is  seen  to  be  already  divided  into  four  parts,  and  the  whole  is  sur- 
rounded by  the  parenchyma  of  the  prothallium.  A  X  200  ;  B  and  C  X  300.— After 
Hofmeister. 

which  the  surrounding  tissue  of  the  archegonium  is  pro- 
longed into  a  four-sided  tube.  At  the  period  of  maturity  of 
the  archegonium,  the  projecting  cells  diverge  from  each 
other,  and  form  an  open  channel  to  the  germ-cell  (B,  Fig. 
250). 

478. — After  fertilization  the  germ-cell  undergoes  division 


366 


BOTANY. 


into  four  cells  (C,  Fig.  250),  and  from  these  the  young  plant 
of  the  asexual  generation  is  developed.  The  young  plant  is 
quite  simple,  having  small  internodes,  bearing  sheaths  which 
contain  but  three  leaves  ;  lar- 
ger shoots  soon  arise,  with  lar- 
ger internodes  and  sheaths  hav- 
ing more  leaves,  and  these  are 
followed  by  others  still  larger, 
until  at  last  the  full  size  is 
reached. 

479.  —  The  spores  of  the 
Equisetinae  are  produced  either 
upon  the  ordinary  green  stems, 
as  in  Equisetum  limosum  and 
E.  hyeniale,  or  upon  colorless 
or  brownish  stems,  which  de- 
velop early,  and,  after  bearing 
the  spores,  die  and  disappear, 
as  in  E.  Telmateia  and  E. 
arvense.  The  sporangia  are 
developed  upon  m  o  d  i  fi  e  d 
leaves,  upon  the  ends  of  the 
stems.  The  spore  -  bearing 
leaves,  like  the  ordinary  ones, 
are  in  whorls ;  each  leaf  is, 
however,  peltate  in  form,  and 
borne  upon  a  short  stalk  (st, 
Fig.  251,  B}.  These  peltate 
leaves  (usually  called  the  pel- 
tate  scales)  are  collected  into 
.  cone-shaped  clusters,  and  by 

their  mntual  pressure  each 

een  cut  o ;  y,  section  of  the  rachis  of  scale     becomes      more     Ol'     leSS 
the   ppike.      U,    peltate    scales,    #,  s,  in  .  ...  TT 

various    position*    (slightly  matrniflert) ;  hexagonal    111    Outline.        Upon 

*ff, the  sporangia  borne  on  the  under  side  ,,  ,  .  .          ,  , 

of  the  scales  ;  gf,  st,  the  pedicels  of  the  the  Under  SUrfaCC  of  each  SCale 

there  arise  five  to  nine  or  ten 

cellular  masses,  which  enlarge  and  become  sac-shaped  spo- 
rangia ;  certain  inner  cells  become  spore  mother-cells,  and 
from  each  of  these  four  spherical  spores  are  produced.  The 


EQUISETIN&  367 

sporangia,  when  mature,  appear  as  nearly  cylindrical  sacs 
attached  by  one  end  to  the  under  surfaces  of  the  peltate 
scales  (sg,  Fig.  251,  B);  they  open  at  maturity  by  a  slit  along 
the  inner  face — i.e.,  the  side  next  to  the  pedicel  of  the  pel- 
tate scale. 

48O. — In  their  development  the  spores  acquire  three  con- 
centric coats,  and  as  they  approach  maturity  the  outer  one, 
which  has  previously  become  spirally  thickened,  splits  from 
two  opposite  points  into  four  narrow  spiral  filaments,  which 
are  united  with  one  another  and  the  spore  at  a  common 
point.  These  filaments  are  hygroscopic,  and  they  roll  and 
unroll  with  the  slightest  changes  in  the  moisture  of  the  air  : 
when  moistened  they  wrap  tightly  around  the  spore,  but 
when  dry  they  unroll  and  become  more  or  less  reflexed.  By 
the  changes  of  position  which  they  undergo,  they  move  the 
spores  very  considerably,  and  are  doubtless  useful  in  empty- 
ing the  sporangia  after  dehiscence — hence  they  have  been 
called  Elaters. 

481. — The  spores  germinate  soon  after  falling  upon  water 
or  moist  earth  ;  they  first  enlarge,  and  then  divide  by  a  par- 
tition into  two  parts  of  unequal  size,  the  larger  of  which 
contains  chlorophyll  granules,  while  the  smaller  one  is  color- 
less ;  the  latter  grows  rapidly  into  an  elongated  root-hair. 
The  larger  cell  divides  first  into  two  cells,  and  then  usually 
one  of  these  divides  again,  and  so  on,  giving  rise  to  a  simple 
prothallium,  composed  of  a  single  layer  of  cells ;  this  en- 
larges and  increases  in  size,  until  it  reaches  the  stage  in 
which  it  bears  the  sexual  organs  (paragraph  475). 

482.  Tissues. — The  epidermis  is  remarkable  for  the  large 
quantity  of  silica  which  it  contains,  mainly  in  the  outer 
walls  of  the  cells.  The  epidermal  cells  are  mostly  narrow 
and  elongated,  and  are  arranged  in  vertical  rows.  The  sto- 
mata,  which  are  present  in  all  the  chlorophyll-bearing  parts 
of  the  plant,  are  arranged  with  more  or  less  regularity  in 
longitudinal  rows  ;  on  the  stem  they  occur  in  the  channels 
between  the  numerous  ridges.  They  resemble  pretty  closely 
the  stomata  of  the  Phanerogams  in  their  structure.  The 
fibro- vascular  bundles  of  the  stem  are  disposed  in  a  circle,  as 
seen  in  a  cross-section,  and  they  run  through  the  fundu- 


-       BOTANY. 

mental  tissues  from  node  to  node,  parallel  with,  but  inde- 
pendent of,  one  another.  At  the  nodes  they  split  into  two 
branches,  which  unite  right  and  left  with  corresponding 
branches  of  other  bundles,  and  thus  form  the  bundles  of  the 
next  internode.  The  bundles  of  successive  internodes  thus 
alternate  with  one  another.  Each  leaf  of  the  leaf-sheaths 
sends  down  a  bundle,  which  joins  a  bundle  in  the  stem  at 
the  point  where  two  descending  branches  of  contiguous  bun- 
dles from  the  upper  internode  unite  to  form  a  bundle  in  the 
lower  internode.  The  bundles  are  thus  seen  to  be  of  the 
"common"  type — i.e.,  they  are  common  to  both  stem  and 
leaves.  As  to  their  construction,  they  are  collateral,  and 
contain  tracheary,  sieve  and  fibrous  tissues  (paragraph  139, 
and  Fig.  99).  The  remainder  of  the  stem  (the  fundamental 
portion)  is  made  up  for  the  most  part  of  parenchyma ;  in  the 
cortical  portion  of  the  vegetating  shoots  it  contains  an 
abundance  of  chlorophyll,  and  it  is  here  frequently  pene- 
trated by  large  longitudinal  canals  (I,  Fig.  249)  ;  in  the 
medullary  portion  a  great  central  canal  soon  appears  by  the 
rapid  growth  causing  a  rupture  of  the  tissues  (h,  Fig.  249). 
There  are  frequently  found  in  the  hypodermal  portions  of 
the  fundamental  systems  bands  of  thick-walled  tissue,  which 
are  either  sclerenchymatous  or  fibrous. 

(a)  This  class  contains  but  one  living  order,  the  EQUISETACE/E.  hav- 
ing the  characters  of  the  class  as  given  above.  In  ancient  geological 
times  the  Calatnites  and  their  allies  constituted  a  distinct  order,  the 
Ccdamiriece,  now  extinct ;  they  differed  from  the  Equitetacew  in  hav- 
ing fibro  vascular  bundles  which  increased  exogenously.  The  Cala- 
mnriecK  were  represented  in  the  Devonian  by  a  species  of  Aslerophyl- 
lile».  In  the  Carboniferous  period  there  were  many  species  of  the  gen- 
era Calamites,  Calamocladus,  Ca'amostacJiys,  Sphenophyllum,  etc.  In 
the  Permian  the  order  became  extinct. 

(6)  The  order  Equisetacem  includes  but  a  single  genus,  Equisetum, 
which  contains  about  twenty-five  species.  None  of  the  species  attain 
a  great  size,  the  usual  height  being  from  20  to  100  cm.  (8  to  40  inches)  ; 
one  species  (E.  giganteum)  in  tropical  South  America  attains  a  height 
of  9  to  10  metres  (30  feet  or  more),  but  it  is  very  slender,  being  no  morH 
than  20  to  25  mm.  (1  inch  or  less)  in  diameter.  The  silicious  stems  of 
E.  hyemale,  a  common  species,  are  sometimes  used  for  scouring  knives 
and  other  articles. 

(c)  The  germination  of  the  spores  of  Equisetinse  may  be  studied  by 


FILMING.  369 

placing  fresh  spores  in  water,  or  upon  moist  earth  or  inoist  pieces  of 
porous  pottery.  It  must,  however,  he  borne  in  mind  that  within  a  few 
days  after  reaching  maturity  the  spores  lose  their  power  of  germinating. 
(d)  The  oldest  genus  of  this  order  is  Equisetites,  represented  in  the 
Carboniferous  by  several  species.  Equisetum  extends  from  the  lower 
Secondary  (Triassic)  to  the  present. 

§  II.  CLASS  FILICIX^E. 

483. — The  plant-body  of  the  asexual  generation  in  this 
class  consists  of  a  solid  stem,  bearing  roots  and  broadly  ex- 
panded leaves,  the  latter  usually  on  long  petioles.  The 
stems  are  mostly  horizontal  and  underground,  but  in  some 
cases  they  rise  to  a  considerable  height  vertically  in  the 
air.  The  leaves  arise  singly  upon  the  stems,  and  grow  up- 
ward from  the  rhizome  (horizontal  stem),  or  are  borne  as  a 
crown  upon  the  more  or  less  elongated  upright  stem.  The 
leaves  are  in  nearly  all  cases  supplied  with  fibro- vascular 
bundles,  which  run  as  veins  through  the  parenchyma  ;  there 
is  usually  a  prominent  midrib,  upon  each  side  of  which  the 
parenchyma  is  permeated  with  small  veins,  which  are  free 
(running  more  or  less  parallel  from  the  midrib  to  the  margin), 
or  reticulated. 

484. — The  Filicinae  are  for  the  most  part  terrestrial  plants 
of  considerable  size,  a  few  only  being  small  or  of  an  aquatic 
habit.  They  are  all  richly  supplied  with  chlorophyll,  and 
none  are  in  any  degree  parasitic.  Nearly  all  the  species  are 
perennial,  in  some  cases,  however,  dying  down  to  the 
ground  at  the  end  of  the  summer,  the  underground  portions 
alone  surviving  the  winter. 

485. — The  prothallium  in  the  Filicinae  is  a  small  cell- 
ular body,*  composed  in  most  cases  of  chlorophyll-bear- 
ing parenchyma.  It  is  frequently  somewhat  heart-shaped, 

*  Dr.  Farlow,  in  a  paper  on  "  An  Asexual  Growth  from  the  Pro- 
thai]  us  of  Pteris  cretica,"  in  P>">c.  Am.  Acad.  Arts  and  Sciences,  1874, 
and  Qr.  Jour.  Mic.  Science,  1874,  described  certain  prothallia  in  which 
scalariform  vessels  were  found  by  him.  These  abnormal  prothallia 
produced  new  plants  directly,  without  the  intervention  of  the  usual 
process  of  fertilization  ;  the  scalar! form  vessels  of  the  prothallia  were 
in  every  case  continuous  with  those  in  the  new  plants. 


370 


BOTANY. 


and  is  generally  provided  with  root-hairs  on  its  under  sur- 
face, by  means  of  which  it  secures  nourishment  for  its  inde- 
pendent growth  (Fig.  252).  In  the  Rhizocarpece  the  pro- 
thallium  is  so  reduced  as  to  be  only  a  small  outgrowth  of  the 
germinating  spore. 

486. — Both  kinds  of  sexual  organs  usually  occur  upon  the 
same  prothallium.  The  antheridia  consist  of  a  few  or  many 
sperm-cells,  which  may  or  may  not  be  surrounded  by  a  wall 


FIG.  253. 


Fig.  252. — A  prothallium  of  a  fern,  seen  from  the  under  fide.  //,  the  root-hairs  grow- 
ing from  the  basal  end  of  the  prothallium  ;  an,  the  anlhcridin  sc;iitcred  among  the 
root-hairs  ;  ar,  archegonia  near  the  apex,  x  10.— After  Prantl. 

Fig.253.— Mature  antlieridimn  of  .-1  iliiintinn  Ciiirillxs-Veiit'rix.  />.  cells  of  prothal- 
lium :  n,  wall  of  antheridium— the  sperm-cells  are  seen  escaping,  in  each  a  sperma- 
tozoid  is  coiled  up  ;  «,  thespermato/oids  ;  b,  the  protoplasm  of  the  sperm-cells  still 
attached  to  the  spermatozoids.  x  550.— After  Sachs. 

of  other  cells.  In  the  Ferns  (Filices)  they  are  few-celled 
bodies,  which  project  from  the  basal  portion  of  the  under 
surface  of  the  prothallium  ;  one  of  the  interior  cells  becomes 
divided  into  sperm-cells,  in  each  of  which  is  a  spirally  coiled 
spermatozoid  (Fig.  253).  In  the  other  orders  the  antheridia 
are  not  confined  to  the  under  surface  of  the  prothallium,  and 
in  some  of  the  Rhizocarpew  nearly  the  whole  of  the  contents 
of  a  microspore  is  developed  into  one  antheridium  tilled 
with  sperm-cells. 


FILMING. 


371 


cells 


.  254.— Young  archegonium 
jrisserrulata,  showing  a  few 
of  the  prothallium,  contain- 
ing chlorophyll,  and  the  axial  row 
of  cells  and  the  germ-cell,  filled 
with  dense  and  granulated 
ilasm.  Highly  magnif 


487.  —  The  archegonia  of   the   Ferns  are  cellular  projec- 
tions from  the  anterior  portion  of  the  under  surface  of  the 
prothallium.     The  germ-cell  is  sit- 

uated at  the  base  of  an  axial  row 
of  cells  ;  the  latter  dissolve,  and  thus 
form  a  canal,  which  becomes  open 
by  the  separation  of  the  apical  cells 
of  the  archegonium  wall  (Fig.  254). 
The  archegonia  of  the  other  Fili- 
cinae  do  not  differ  much  as  to  struc- 
ture, but  like  the  antheridia,  they 
are  not  confined  to  the  under  sur- 
face of  the  prothallium. 

488.  —  After    fertilization     the 
germ-cell   divides    (in    the   known 

,-,       .      toplasm.       1 

cases)  into  four  parts,  as  in  Equi-  After  Sachs. 
setince,  and  by  the  growth  and  development  of  these  the 
young  plant  of  the  asexual  generation  is  produced.  The 
young  plant  is  at  first  very  simple,  the 
first  leaves  being  much  smaller  and  less 
divided  than  those  which  appear  later 
(Figs.  255  and  256). 

489.  —  The  spores  are  developed  upon 
the  leaves.  They  are  contained  in  spo- 
rangia, which  occur  singly  or  in  clusters 
upon  the  surface,  or  on  the  margins  of 
the  more  or  less  modified  leaves  ;  in  one 
order,  the  Opliioglossacecv,  the  single  spo- 
rangia occur  in  the  tissues  of  the  greatly 
modified  leaves.  The  spores  are  all  of  one 
255  —  Prothai  kind,  excepting  in  the  Rhizocarpetz,  in 
which  there  are  two  sizes,  viz.,  micro- 

--  n  ' 

,          from  below,  spores  and  macrospores.     The  sporangia 

p,  the    prothallium;    h,       .   .  ,  -,-.  /  7-7-7  •       \  -,  •  . 

root-hairs  of  prothallium;  of  the  true  Ferns  (Fihces)  have  a  ring  of 
p\antf  u>',  th»  finTfocf  cells  belonging  to  their  walls,  peculiarly 
t-  thickened,  forming  an  elastic  ring,  which 
ruptures  the  mature  sporangium  ;  in  the 
other  orders  there  is  no  such  elastic  ring,  and  the  dehiscence 
is  usually  by  the  simple  splitting  of  the  dried  wall. 


PH 

Hum  and  young  plant  of 

Ad'Miitnm   ('apillus-Ven 


, 

toeth8eecondnfootan 


372 


BOTANY. 


490. — The  Filicinae   may  be  here  arranged  under  four 

orders,  as  follows  :* 
/.     IsosporecB. — 
Spores     of     one 
kind. 

Order  1.  Pilices, 
the   true   Ferns. 


Pig.   256. — Prothallium    and    you 
antum  CapUlus-Veneris,  seen    in  v 
section.    p,p,  the  prothallium  ;  a,  archegonia  :  A,  root- 
hair  ;  E,  the  young  plant ;   u\  its  first  root ;  b,  its  first 
leaf,    x  about  10.— After  Sachs. 


Sporangia  compos- 
longitudinal    ed  of  modified  tri- 


ehoroes,   each    de- 
veloped from  a  sin- 


gle epidermal  cell,  produced  in  clusters  on  the  surface  of  or- 
dinary   or    slightly    modified 
leaves.         Each     sporangium 
with  an  elastic  ring.     No  stip- 
ules. 

Order  2.  Marattiaceae,  the 
Ringless  Ferns.  Sporangia 
produced  from  a  group  of  epi- 
dermal cells ;  the  ring  either 
rudimentary  or  wanting.  The 
large,  much  -  branched  leaves 
with  stipules. 

Order  3.  Ophioglossacese, 
the  Adder-Tongues.  Sporan- 
gia formed  by  groups  of  cells 
in  the  interior  of  a  modified 
branch  of  the  sheathing  leaf. 
The  ring  is  absent. 

//.  Heterosporece.  —  Spores 
of  two  kinds. 

Order  4.  Rhizocarpeee,  the 
Pepperworts.  Sporangia  com- 
posed of  modified  trich- 
omes  (?);  the  microsporangia 
containing  many  microspores,  »ne  of  the  stem.-After  Sachs.' 

*  This  arrangement  is  essentially  that  modification  of  Sachs'  pro- 
posed by  Professor  McNab.  See  his  "  Outlines  of  the  Classification  of 
Plants,"  American  edition,  Chapter  VII. 


slightly  enlarged,  r,  brown  sclerenchy- 
ma,  forming  a  hard  (-heath  beneath  the 
epidermis ;  p,  colorless  parenchyma  of 
the  fundamental  system  ;  ig,  inner  fibro- 
vascular  bundles ;  ag,  the  broad  upper 
band  of  the  outer  bundle  /one ;  pr,  a 
band  of  elongated  thick-walled  cells, 
sclerenchyma  or  fibrous  tissue — a  second 
one  occurs  on  the  other  side  of  the  cen- 
tral bundles.  Ji,  the  separated  upper 
fibro-vascular  bundle  of  the  stem  (rhi- 


FILICES. 


373 


the  macrosporangia  usually  containing  only  one  macrospore. 
Sporangia  in  clusters,  enclosed  in  modified  leaves  or 
"fruits." 

Order    Filices,  the  true  Ferns.     The  prothallia  of  the  Ferns  are 
green  thallus-like  structures,  growing  upon  the  surface  of  the  ground, 


Fig.  257a.— Longitudinal  section  of  the  apex  of  the  root  of  Pteris  hastata.  v, 
apical  cell  ;  o,  o,  epidermis  ;  e,  cortical  tissue  ;  c-c,  c-c,  the  primary  flbro-vascular 
bundles  ;  n,  m,  I,  k,  the  root -cap  ;  k,  k,  daughter-cells  recently  cut  off  from  the  apical 
cell.-After  Nageli  and  Leitgeb. 

and  composed  at  first  of  but  a  single  row  of  cell?,  but  later  of  extended 
layers  of  cells.  Th-  are  monoecious,  and  bear  their  antheridia  on  the 
basal  portion  of  t1  ander  surface,  while  the  archegonia  are  found  near 
the  apical  margin  of  the  same  surface.  After  fer- 
tilization the  germ-cell  divides  into  four  parts,  the 
uppermost  one  (or  two)  of  which  becomes  the  foot, 
or  organ  which  remains  in  contact  with  the  prothal- 
lium  ;  one  of  the  other  parts  develops  into  the  first 
root,  and  the  other  into  the  first  leaf.  The  young 
plant  is  thus  formed  on  the  under  side  of  the  pro- 
tliallium,  from  which  it  grows  up  as  shown  in  Figs. 
250  and  255. 

The  steins  of  Ferns  are  mostly  short,  or  slender 
and  creeping  in  our  species,  but  in  the  tropics  they 
are  often  of  considerable  height  and  thickness,  Fe'af  "of" Poiypodium, 
some  tree-ferns  attaining  the  height  of  24  metres  Le^Maout^aiid^De- 
or  more  (80  feet  or  more).  They  increase  in  length  caisne. 
only,  and  this  takes  place  by  the  continued  division  of  an  apical  cell 
They  contain  flat  fibro-vascular  bundles  (Fig.  257,  A  and  B),  which  are 
usually  disposed  in  a  single  circle,  as  seen  in  a  cross-section,  but  in 
some  cases  there  are  bundles  in  the  medullary  portion  also.  On  ac- 
count of  the  presence  of  thick  masses  of  thick-walled  cells,  (scleren- 


374  BOTANY. 

chynia,  or  fibrous  tissue),  the  stems  are  frequently  very  hard.  The 
fundamental  tissues  frequently  develop  a  good  deal  of  mucilaginous  or 
slimy  matter. 

Both  stems  and  roots  develop  from  a  three-sided  apical  cell.  Tl.e 
apical  cell  of  the  root  continually  undergoes  fission  not  only  parallel  to 
its  sides,  but  also  parallel  to  its  base — i.e.,  at  right  angles  to  the  axis  of 
the  root.  The  daughter-cells  thus  cut  off  (k,  k,  Fig.  257a)  constitute  the 
root-cap  (pileorhiza)  with  which  each  root-tip  is  covered. 

The  leaves,  which  unfold  circinately,  are  often  very  large,  and  in 
most  cases  are  more  or  less  lobed  and  divided,  frequently  becoming 
several  times  compound.  Their  development  is  slow,  the  rudiment  of 
the  petiole  forming  one  year,  and  that  of  the  blade  the  next,  while  the 
opening  or  unfolding  does  not  take  place  till  the  following  year.  The 
growth  is  sometimes  periodic,  as  in  Gleichenia  and  Lygodium.  In  the 


FIG.  258.  FIG.  259.  FIG.  260. 

Fig.  258.— Under  side  of  a  fertile  leaflet  of  Aspidium  FUix-mas,  .with  eight  sori. 
i,  the  indusium.  Magnified.— After  Sachs. 

Fig.  259. — A  leaflet  of  Ax]il<ininm,  showing  the  elongated  nori,  each  covered  by  a 
laterally  placed  indusium. — From  Le  Maout  and  Decaisne. 

Fig.  260. — A  leaflet  of  Ac/iantum,  showing  the  sori  covered  by  indusia  formed  by 
reflexions  of  the  margin  of  the  leaflet.— From  Le  Maout  and  Decaisne. 

latter  the   leaf  eventually   becomes  greatly   elongated,   resembling  a 
climbing  stem. 

The  sporangia  are  usually  formed  in  clusters  (sori)  on  the  veins,  on 
the  under  side  of  the  leaves,  or  upon  their  margins.  The  sori  may 
be  distinct  and  rounded  or  more  or  less  elongated,  or  they  may  be 
confluent  over  considerable  portions  of  tlie  surface.  In  some  cases 
the  sori  are  naked  (as  in  Fig.  2576),  but  quite  frequently  each  one 
is  covered  by  a  cellular  outgrowth  of  the  leaf,  called  the  induintnn 
(Figs.  258,  259,  260).  In  some  cases  the  indusium  is  shield-shaped,  its 
short  pedicel  arising  in  the  midst  of  the  sporangia  (Figs.  258  and  261) ; 
in  others  it  is  more  or  less  elongated,  and  attached  by  one  of  its  edges 
to  the  side  of  the  sorus  (Fig.  259) ;  in  still  others  a  portion  of  the  mar- 
gin of  the  leaf  is  refl^xed  in  such  a  way  as  to  form  the  covering  (Fig.  260). 
Many  other  forms  are  common,  and  are  to  be  found  described  in  system- 
atic treatises.  The  sporangia  are  more  or  less  rounded  bodies,  usually 


FILICES. 


375 


borne  upon  slender  pedicels.  Morphologically  they  are  trichomes, 
which  undergo  a  special  modification.  Each  sporangium  is  at  first  a 
two-celled  trichome  ;  the  lower  cell  of  which  develops  into  the  pedicel, 
while  the  other  becomes  divided  by  partitions  parallel  to  its  surface 
into  outer  cells,  which  develop  into  the  sporangia!  wall,  and  an  inner 


Fig.  Kl.—Aspidium  Mlix-ma*.  A,  a  section  of  a  leaf  through  a  sorus  ;  «,  «.  the 
sporangia,  borne  upon  an  elevated  mass  of  tissue,  the  receptacle  ;  i,  I,  the  indusium, 
seen  in  section.  B,  a  section  of  a  young  sporangium,  showing  its  central  cell  divided 
into  four  ;  r,  one  cell  of  the  ring,  the  section  being  at  right  angles  to  its  plane.  C,  a 
sporangium  nearly  mature,  seen  laterally  ;  r,  r,  the  ring  of  the  sporangium ;  d,  a 
glandular  hair— in  the  interior  of  the  sporangium  are  seen  the  nearly  ripe  spores. 
Magnified.— After  Sachs. 

tetrahedral  cell  (the  so-called  central  cell),  rich  in  protoplasm  ;  from  the 
latter  a  number  of  spore  mother-cells  (twelve,  according  to  Reess)  are 
formed,  and  from  each  spore  mother-cell  four  spores  arise  (Figs.  261 
and  262).  In  each  sporangium  some  of  the  cells  of  the  wall  are  devel- 
oped into  an  elastic  ring  (annnl)is),  which  extends  part  way  around  the 


376 


BOTANY. 


spore  cavity  (Fig.  261,  C,  r).     By  the  contraction  of  this  ring  the  ripe 

sporangium  is  ruptured  and  the  spores  set  free.    In  some  cases,  instead 

of  forming  a  ring,  the  elastic  cells  are  arranged  as  a  group  at  one  side 

or  end  of  the  sporangium. 

Six  families  or  suborders  of  the  Ferns  may  be  distinguished,  if  we 

take  into  consideration  the  characters  derived  from  the  asexual  genera- 

tion.    They  have  been  arranged  as  follows  :  * 
1.  GleicheniacecB.  —  Sporangia  sessile,  splitting  vertically,  furnished 

with  a  complete  horizontal  ring.   Sori  composed  of  very  few  sporangia  ; 

receptacle  not  elevated  (Fig.  263).     Fronds  with  very  distinct  dichot- 

omous  branching.     Genera   two  (Platyzoma  and  Oleichenia)  ;  species 

thirty,  mostly  confined  to  the  southern  hemisphere. 

2.  Ilymenophyllacem.  — 
Sporangia  sessile,  split- 
ting vertically,  furnish- 
ed with  a  complete 
horizontal  ring.  Sori 
composed  of  numerous 
sporangia  inserted  on  a 
long  filiform  receptacle 
(Fig.  264).  Leaves  of 
filmy  texture  (usually  of 
a  single  layer  of  cells), 
with  pinnate  branching. 
Genera  two  (Hymeno- 


II.,  the  same  after  the  absorption  of  the  nucleus  ; 
///.,  the  mother-cell,  with  two  large  clear  nuclei— 
sometimes  a  line  of  separation  is  evident,  as  in  the 
figure  ;  IV.,  the  mother-cell,  with  four  clear  nuclei, 
which  appear  after  the  absorption  of  the  two  in 
///.,•  V.,  the  four  daughtt-r-cc-lls  (young  spores) 
which  form  from  IV.  ;  VI.,  VII.,  VIII.,  different 
relative  positions  of  the  'developing'  spores';  /jr.,  the 
perfect  epore.  x  550.—  After  Sachs. 


nfs)  ;  species  150  to  200, 

„„,!„    ~~nfin~A     +       *v, 
mostly   confined    to    the 

tropics. 

J,      ~       ,  „ 

o.    Cyathcacea>.  —  Spo- 

rane-ia      nearlv       sessile 
r&"gla  *\le> 

splitting       transversely, 


*  The  characters  and  arrangement  of  the  suborders  of  ferns  are 
taken  from  the  article  "  Ferns,"  by  W.  T.  T.  Dyer  and  J.  G.  Baker,  in 
the  "  Encyclopaedia  Britannica,"  ninth  edition,  Vol.  IX.,  p.  104.  For  a 
systematic  account  of  the  Ferns  the  student  is  referred  to  "  Synopsis 
Filicum  :  a  Synopsis  of  all  Known  Ferns,"  by  W.  J.  Hooker  and  J.  G. 
Baker,  London,  1873  The  student  may  profitably  consult  the  following 
recently  published  American  works,  viz  ,"  The  Ferns  of  North  America," 
by  D.  C.  Eaton,  the  plates  by  J.  H  Emerton,  now  being  issued  in  parts  ; 
"Ferns  of  Kentucky  "  by  John  Williamson,  1878  ;  "  Ferns  in  Their 
Homes  and  Ours,"  by  John  Robinson,  1878  ;  and  "  Ferns  of  the  South- 
west," by  D.  C.  Eaton,  in  Lieut.  Wheeler's  "  Report  upon  U.  S.  Geo- 
graphical Surveys  West  of  the  One  Hundredth  Meridian,"  Vol.  VI, 
1878  ;  Underwood's  "  Our  Native  Ferns,"  1H81. 


F1LICES. 


377 


furnished  with  a  usually  incomplete,  nearly  vertical,  or  rather  oblique 
ring.  Receptacle  prominent,  barrel-shaped  (Fig.  265).  Tree-ferns. 
Genera  three  (Cyathea,  Hemitelia,  and  Alsophila) ;  species  150,  mostly 
tropical  and  subtropical. 

4.  Polypodiacem. —  Sporangia   stalked,   splitting   transversely,  fur- 
nished with  a  usually  incomplete  vertical  ring.     Receptacle  not  prom- 


FIG.  2(33.  PIG.  264.  FIG.  265. 

Fig.  263.— Portion  of  a  leaf  of  Gleicfienia,  with  a  sorus,  a  ;  b,  a  sporangium.— Af- 
ter Hooker. 


Fig.  264.— Portion  of  a  leaf  of  Trichomane*,  a,  with  five  sori 
After  Hooker. 


a  sporangium. — 


Fig.  265.— Vertical  section  of  a  sorus,  a,  of  Alsophila,  showing  the  cylindrical  re- 
ceptacle ;  ft,  a  sporangium. — After  Hooker. 

inent  (Figs.  2576  to  261).  Genera  fifty  (Acrostichum,  Polypodium, 
Adiantum,  Pteris,  Asplenium,  Scolopendrium,  AspidHm,  Cysiopteris, 
etc.) ;  species  2000,  widely  distributed  throughout  the  world. 

5.  OsmundacecK. — Sporangia  stalked,  splitting  vertically,  furnished 
with  only  a  faint  horizontal  bar,  instead  of  a  ring  (Fig.  266).     Genera 
two  (Osmunda  and  Todea) ;  species  ten  to  twelve,  widely  distributed  in 
north  and  south  temperate  re- 
gions. 

6.  Schizceacea.  —  Sporan- 
gia sessile,  splitting  vertical- 
ly, crowned    by   a   complete 
small  annular  horizontal  ring 
(Fig.   267).       Genera    five 
(^chizcea,  Anemia,  Lygodium, 
etc.);    species  sixty,    mostly 
natives  of  the  warm  regions 
of  America  and  Asia. 

Economically  the  true  Ferns  are  of  comparatively  little  value.  The 
pulpy  interior  of  the  stem  of  a  tree-fern  (Cyathea  medullaris)  growing 
in  the  Pacific  islands  furnishes  an  important  article  of  food  to  the 
natives.  In  Australia  the  underground  steins  of  Pteris  aquilina 
supply  an  indifferent  food.  A  few  species  are  of  doubtful  value  as 
astringent  medicines.  The  long  woolly  hairs  of  certain  species  ol 


FIG.  267. 


Fig.  266.  —"Two  sporangia  of  Osmunda;  a, 
with  the  rudimentary  ring  uoen  in  front  view  ; 
b,  with  the  ring  seen  in  profile.— After  Hooker. 

Fig.  267.— Lower  portion  of  a  fertile  pinna,  a, 
of  Schizcea  ;  b,  a  sporangium. — After  Hooker. 


378  BOTANY. 

Dicksonia  growing  in  the  Sandwich  Islands  constitute  the  substance 
known  as  Pulu,  used  somewhat  in  upholstery.  Many  ot  the  species 
are  now  largely  grown  as  ornaments. 

Ferns  first  appeared  in  the  Devonian,  in  which  period  no  less  than 
twelve  genera  belonging  to  extinct  families  were  represented.  In  the 
Carboniferous  the  genera  and  species  were  exceedingly  numerous,  after 
which  they  decreased  to  the  present.  Many  Tertiary  genera  extend  to 
the  present,  and  are  now  represented  by  living  species. 

Order  Marattiaceee,  the  Ringless  Ferns.  The  prothallia  of  the 
ringless  Ferns  are  thick,  fleshy,  and  dark  green  in  color.  They  bear 
antheridia  in  depressions  upon  both  surfaces,  and  in  these  are  pro- 
duced spermatozoids  bearing  much  resemblance  to  those  of  true  Ferns. 
The  archegonia  are  also  deeply  sunken  in  the  tissue  of  the  prothallium, 
and,  according  to  M>-Nab,  resemble  those  of  the  Rhizocarpeae. 

The  asexual  generation  bears  a  close  resemblance  to  that  of  true 


FIG.  268.  Fio.  269. 

Pig.  268.— A  prothallinm  of  Bottychium  Lunaria,  in  longitudinal  section,  ac,  an 
archegonium  ;  an,  an  antheridluni— near  to  it  are  others,  one  not  yet  mature,  and 
three  empty  ones  ;  w,  root-hairs.  X  50. — After  Hofmeister. 

Fig.  2t>9.— A  longitudinal  section  of  the  lower  part  of  a  young  plant  of  the  same,  dug 
up  in  September,  st,  stem  ;  b,  b',  b",  leaves,  x  20.-Affer  Hofmeister. 

Ferns.  The  plant-body  is  usually  large  ;  its  stem  is  generally  upright, 
short,  thick,  and  unbranched  ;  the  leaves  are  circinately  developed,  as 
in  true  Ferns,  and  are  mostly  very  large,  with  pinnately  or  palmately 
divided  laminae  ;  they  are  provided  with  stipules,  and  in  their  petioles 
is  found  the  first  collenchyma.  The  stem  develops  from  a  three-sided 
apical  cell,  but  the  root  is  provided  with  a  group  of  cells,  as  in  the 
Phanerogams. 

The  sporangia  occur  on  lateral  veins  upon  the  under  side  of  the 
leaves,  and  are  usually  confluent  into  one  body,  the  sorus  (often  called 
erroneously  the  sporangium).  In  Angiopleris,  however,  the  sporangia 
are  distinct.  The  spores  develop  from  many  mother-cells  in  each  spo- 
rangium, instead  of  from  one,  as  in  true  Ferns. 

The  Marattiaceae  are  essentially  tropical,  extending  somewhat  into 
the  warmer  parts  of  the  temperate  zones.  Four  genera  are  known, 
viz. ,  DanuRa,  restricted  to  tropical  America ;  Kaidfusteia  and  Angioptei*is, 


OPHIOGLOSSACE^. 


379 


found  in  the  tropical  regions  of  the  eastern  hemisphere  ;  and  Marattia, 
which  is  represented  in  the  New  and  Old  World.  The  whole  number 
of  species  probably  does  not  exceed  twenty-five. 

The  oldest  members  of  this  order  oc- 
cur in  the  Permian  strata. 

Order  Ophioglossaceae,  the  Adder- 
Tongues.  The  prothallia  of  these  fern- 
like  plants  are  thick  masses  of  paren- 
chyma, which  are  destitute  of  chloro- 
phyll ;  they  develop  underground,  and 
are  difficult  to  study,  hence  they  are 
known  for  but  few  of  the  species.  In 
Botvychium  Lunaritt,  according  to  Hof- 
meister,*  the  prothallium  is  "an  oval 
mass  of  firm  cellular  tissue,  whose  larger 
diameter  does  not  exceed  a  millimetre 
(one  twenty-fifth  of  an  inch),  and  is  often 
less"  (Fig.  268).  He  discovered  them 
in  the  ground  at  a  depth  of  from  two 
and  a  half  to  seven  and  a  half  centim- 
etres (one  to  three  inches).  The  an- 
theridia  occur  for  the  most  part  upon 
the  upper  surface,  and  the  archegonia 
upon  the  lower. 

The  mature  plant  (asexual  generation) 
consists  of  a  short  erect  underground 
stem,  which  bears  annually  one  or  more 
stipulate  and  erect  (i.e.,  not  circinate)f 
leaves  (Fig.  269,  &'  and  b",  and  Fig. 
270).  The  leaf  is  usually  divided  into 
two  portions,  one  of  which  is  green  and 
expanded  (Fig.  270,  b),  while  the  other 
is  contracted  into  a  spore-bearing  organ 
(Fig.  270,  /)  ;  in  some  cases  each  seg- 
ment is  simple,  while  in  others  it  is  one 
or  more  times  compound. 

The  spores  of  the  Ophioglosaaceai  are 
produced  from  mother-cells  developed  in 

the  tissue  of  tlie  fertile  segment  of  the  Lun  ana,  nat.  size,  st,  st,  th'e  short 
leaf;  hence  the  so-called  sporangia  of  JW'Jffi  ft  ^ftiESi 
this  order  are  morphologically  quite  into  the  sterile  part  (6)  and  the  fer- 
different  from  those  of  true  Ferns. 


Pig.  270.-Plant  of  Botrychium 


*  "  On  the  Germination,  Development,  and  Fructification  of  the 
Higher  Cryptogainia,"  etc.,  by  Dr.  Wilhelm  Hofmeister.  Translated 
by  Frederick  Currey,  London,  1862. 

f  The  vernation  of  our  species  of  Botrychium  is  well  worked  out  iu 


380 


BOTANY. 


The  stems  are  developed  from  a  triangular  apical  cell,  while  the 
roots,  like  those  of  Marattiacece,  possess  no  apical  cell,  but  a  group 
of  cells  instead.  The  tibro-vascular  bundles  are  arranged  in  a  cylinder 
(a  circle  in  cross-section),  and  they  form  a  network  by  their  anastomos- 
ing with  each  other.  According  to  De  Bary,  they  belong  to  the  "col- 
lateral "  series. 

These  plants  are  usually  of  small  size,  rarely  exceeding  30  centime- 

<s^ 
<8>, 

B 


Fig.  271.—  A,  vertical  section  of  an  archogoninm  and  the  rudimentary  prothallium 
of  Pilvlaria  globulifera  ;  tv,  w,  part  of  the  ruptured  wall  of  the  macrospore  ;  p,  p 
the  rudimentary  prothallium.  merging  above  into  the  archegoninm  ;  a,  the  germ-cell 
ready  for  fertilization  ;  «c.  the  cavity  of  the  macrospore.  X  500.  B.  a  microspore 
of  the  same  hurst  open  and  allowing  the  escape  of  sperm-cells.  «.  from  which  sper- 
matozoids  are  escaping.  X  600.  C  ,  longitudinal  section  of  n  macrospore  of  Salrin'm 
natana  at  the  commencement  of  germination  ;  p.  the  young  protlmllium.  x  30.  D, 
a  very  young  prothallinm  of  the  same,  detached,  with  a  fragment  of  the  inner  spore- 
membrane  (m)  adhering  to  it—  top  view.  X  2(0.  E,  a  vertical  longitudinal  section  of 
D.  X  200.  F  a  similar  section  of  a  more  advanced  prothallium  of  the  same  ;  g.  the 


. 

young  germ-cell.  X  200.  G,  vertical  section  of  an  unfertilized  archegonium  of  the 
same,  surrounded  hy  cells  of  the  prothallium  ;  g,  germ-cell  ;  ar,  canal  of  the  arche- 
gonium. x  300.—  After  Hofmeister. 

tres  (1  foot)  in  height  ;  in  one  Ceylonese  species  (Ophioglo&sum  pendu- 
lum) the  slender  pendent  leaves  are  sometimes,  according  to  Hooker, 
nearly  three  metres  long  (15  feet). 

There  are  three  genera,  viz.,  Ophiofflossxm,  JtotryeJiium,  and  Helmin- 
;  the  latter  is  confined  to  the  southern  hemisphere,  the  others 


(J.   E.   Davenport's  paper,  Verimtimt  in   l!»trt/<-hi<i.  in  the  bulletin  of 
t/u  'I'urrey  Botanical  Club,  1878;  it  is  illustrated  by  figures. 


HHIZOCARPE^E. 


381 


are  cosmopolitan.  All  told,  there  are  probably  not  more  than  eighteen 
or  twenty  distinct  species,  of  which  we  have  six  within  the  limits  of 
the  United  States. 

A  species  of  Ophioglos-um  has  been  discovered  in  the  Tertiary  strata. 
Order    Rhizocarpeee,    the    Pepperworts.      The  prothallia  of    the 
Rhizocarps   are   dioecious,  and  are  developed 
from  two  kinds  of  spores  (the  mac  ospores  and 
microspores,  to  be  more  particularly  described 
below).     The  antheridia  are  simple,  and  con- 
sist of  small,  few-celled  outgrowths  from  the 
germinating  microspore  (in  isalvinia,  and  Azol- 
la),  or  of  the  transformed  contents  of  the  mi- 
crospore (in  Marsilia  and  Pilularia,  Fig.  271, 
B).    The  spermatozoids  are  spirally  coiled,  and 
in  the  two  last-named  genera  are  produced  in 
definite  numbers  (thirty-two)  in  each  antherid- 
ium.    The  prothallia  which  produce  archego- 
nia  are  small,  and  barely  attain  a  size  large 
enough    to   protrude    through    the   ruptured 
wall  of  the  macrospore  (p,  p,  Fig.  271,  A). 
The  archegonia  resemble  those  of  true  Ferns, 
but  are  more  sunken  in  the  tissues  of  the  pro- 
thallia (Fig.  271,  A  and  G).    After  fertilization 
the  germ-cell  undergoes   division,   and  gives 
rise   directly  to  a   leafy  stemmed   plant,    the 
asexual  generation,  provided  with  roots  (ex- 
cept in  Salein.- 
ia).     The  stem 
is       horizontal, 
and  floats  upon 
the     water     or 
runs      through 
the  mud  at  the 
bottom  of  shal- 
low water.  The 
leaves  are   cir- 
cinately   devel- 
oped,   and    are 
simple  or  quad- 
rifid  (Fig.  272). 
The    stem   and 
root        develop 
from   an   apical 
cell,    which     is 
two  or  three-sided  in  the  stem,  and  triangular  in  the  root. 

The  sporangia,  which  are  usually  of   two  kinds,    are   produced  in 
"fruits"  or  receptacles,   which  are  modified  parts  of   leaves.     These 


FIG.  272. 
j.  272.— Plant  of  Marsilia  ealvatrix. 


FIG.  273. 


.  . .  K,  apex  of  the  stem  ; 
b,  b,  leaves  ;  /,  f,  f,  the  fruits  springing  from  the  petioles  at*. 
One  half  rilit,  size.— After  Sachs. 

Fig.  273.  —  Longitudinal  section  through  three  fruit*  (the  fer- 
tile apices  of  a  waier-leaf)  of  talmnia  nutans.  i,  i,  two  fruits 
containing  inicrosporangia  ;  «,  oue  with  macrosporangia.  X  10. 
—After  Sachs. 


382 


BOTANY. 


fruits  are  one-celled  in  Salviniaeea,  and  several-celled  in  Mardliacew. 
In  Salmnia  (Fig.  273)  the  inicrosporangia  are  small  and  numerous,  and 
are  contained  iu  separate  fruits  from  the  macrosporangia,  which  are  few 
in  number  ;  each  of  the  former  contains  many  microspores,  and  the 
latter  a  single  macrospore  (by  the  abortion  of  three,  as  four  are  formed 
at  first).  In  Marsilia  and  Pttularia  the  two  kinds  of  spores  occur  in 
the  same  fruit,  and  in  the  former  in  the  same  sporangium. 

Four  genera  are  known  ;  these  are  arranged  under  two  suborders  or 
families,  the  Salviniacece,  which  includes  fsalvinia  and  Azolla,  and  the 
Marsiliacece,  which  includes  Marsilia  and  Pttularia.  The  whole  num. 
ber  of  species  is  about  fifty,  of  which  thirty  -seven  belong  to  Marsilia, 
the  others  being  about  equally  divided  between  the  remaining  genera. 
All  the  species  are  of  small  size,  rarely  exceeding  a  few  centimetres  in 
height  ;  they  grow  in  ditches  and  other  wet  places.  Three  or  four 
species  occur  in  the  United  States. 

Rhizocarps  have  been  found  as  fossils  in  the  Secondary  (Jurassic)  and 
Tertiary  strata. 


§  III.    CLASS 

491.  —  The  plant-body  of  the  asexual  generation  consists 
of  a  solid,  dichotomously  branched,  leafy,  and  generally  erect 
stem.    The  leaves,  which  have  a  central  fibro-vascular  bundle, 
or  midrib,  are  small,  simple,  sessile,  and  imbricated,  and 
usually  bear  a  considerable  resemblance  to  those  of  Mosses. 
The  roots  are  mostly  slender  and  dichotomously  branched. 

The  Lycopodinae  are  for  the  most  part  terrestrial  peren- 
nials. They  are  usually  of  small  size,  rarely  exceeding  a 
height  of  15  or  20  centimetres  (6  or  8  inches). 

492.  —  The  spores  of  the  Lycopodinae  are  produced  in  spo- 
rangia which  are  generally  (if  not  always)  axillary  appen- 
dages of  the  leaves.     In  four  of  the  genera  (Lycopodiiun, 
Psilotum,  Tmesipteris,  and  Phylloglossum]  the  spores  are 
of  one  kind  ;  while  in  the  two  remaining  genera  (Selaginella 
and  Isoetes)  they  are  of  two  kinds,  the  macrospores  and  the 
microspores. 

493.  —  The  prothallium  or   sexual  generation  is  scarcely 
known  in  the  isosporous  genera  ;  it  appears,  however,  to  be 
a  thickish  mass  of  tissue,  which  develops  underground,  and 

*  Sachs  calls  this  class  the  Dichotomy,  but  as  long  as  we  have  the 
EquisetincB  and  Filicince,  we  may,  for  the  sake  of  uniformity,  retain  the 
old  name  given  above. 


L  YCOPODIN^fi. 


383 


bears  both  kinds  of  sexual  organs.  In  the  heterosporous 
genera  the  macrospores  produce  small  prothallia,  which 
project  slightly  through  the  ruptured  spore-wall,  and  upon 
these  several  or  many  archegonia  are  formed ;  the  micro- 
spores  produce  very  small  rudimentary  prothallia,  each  of 


FIG.  274. 


FIG.  275. 


Fig.  274.  —  A,  longitudinal  section  of  a  young  prothallium  of  Lycopodium  anno- 
tinum  ;  an,  two  antheridia,  not  mature—  upon  its  lower  surface  are  seen  the  root- 
hairs.  X  150.  £,  longitudinal  section  of  a  prothallium,  p,  of  the  same,  after  germi- 
nation of  the  young  plant  ;  s,  stem  of  young  plant  ;  r,  it8  young  root  ;  /,  the  foot,  or 
portion  of  the  young  plant  which  remains  in  contact  with  the  prothallium.  Slightly 
magnified.  -After  Fankhauser. 

Fig.  275.  —  Plant  (asexual  generation)  of  Lycopodium  clavatum  ;  horizontal  stem 
with  roots  and  leaves,  the  erect  branch  bearing  fertile  spikes,  «.  One  half  natural  size. 
—After  Prantl. 

Avhich  bears  a  single  antheridium,  in  which  there  are  de- 
veloped a  few  spermatozoids. 

494.  —  Three  orders  of  Lycopodinse  may  be  distinguished, 
as  follows  : 

7.  IsosporecB.  —  Spores  of  one  kind  ;  no  ligules. 

Order  1.  Lycopodiacese,  with  small  leaves,  commonly 
moss-like. 

//.  HeterosporecB.  —  Spores  of  two  kinds  ;  ligules  present. 

Order  2.  Selaginellse,  with  small  moss-like  leaves. 

Order  3.  Isoeteee,  with  elongated  grass-like  leaves. 


384 


BOTANY. 


Order  Lycopodiacese.— The  prothallium  is  known  only  in  one  case, 
viz.,  Lycopodiunt,  annotinum.  It  was  discovered  underground  by 
Fankhauser  in  1872,  who  described  it*  as  a  yellowish  white,  irreg- 
ularly lobed  body,  sparingly  furnished  on  its  under  surface  with  small 
root-hairs  (Fig.  274,  A).  In  its  upper  surface  the  prothallium  bears 

antheridia,     which    are 
-^  "^  deeply  sunken  in  its  tis- 

sue (an,  Fig.  274,  A); 
the  spermatozoids.which 
are  numerous,  are  stout 
and  slightly  twisted. 
The  archegonia  were 
only  seen  after  the  young 
plants  had  grown  con- 
siderably (Fig.  274,  B) ; 
they  are  likewise  devel- 
oped upon  the  upper 
surface  of  the  prothal- 
lium, and  appear  to  bear 
a  considerable  resem- 
blance to  those  of  the 
Ophioglossacece. 

The  young  plant  which 
results  from  the  growth 
of    the  fertilized  germ- 
cell  is  quite  simple,  but 
it  soon  takes  on  the  form 
of    the    mature    plant. 
The  leaves  are  crowded 
in  Lycopodiuin,  but  are 
Fig.  276  -Germination  of  the  spores  of  Selaffinella.    less  so  in  the  other  gen- 
1,  longitudinal  section  of  a  macrosporc  of  >'.  Mirten-      _          j      manv    snwip"* 
sii/  aWe  the  line  d  is  the  prothallium.  below  it  the    era' 

"  endosperm  ;"  «,«',  two  embryos,  the  larger  one  with  the  sporangia  are  borne 
its  suspsusor  projecting  into  the  neck  of  the  archego-  .  ,,  nY:ia  nt  *!,„  „_ 
nium  ;  at  the  left  of  the  larger  embryo  is  a  young  ar-  m  the  ax"8  of  the  or- 
chegonium  ;  several  root-hairs  are  also  shown.  2,  a  dinary  leaves,  but  in 
voiing  archegonium  of  the  same  species,  not  yet  open.  ,,  ,,  •,  ,  .  , 

3,  an  archegonium  of  the  rame  species,  with  the  germ-  others  the  leaves  which 
cell  fertilized  and  divid.  d  into  two.  A,  a  microspore  bear  sporangia  are  col- 
of  S.  caulescens,  rendered  trans-parent,  showing  the  di-  ,  ,  .  ... 

vision  of  the  contents  into  the  primordial  cells;  the  lected  into  cone-like  or 
small  lower  cell  is  the  rudimentary  prothallinm.  />,  Rnibfi  like  structures 
later  stage  of  the  same,  showing  thelarge  antheridium  SplK6  '  "K6  Te8' 

filled  with  sperm-cells  ;  v,  the  rudimentary  prothal-  which  terminate  certain 
Hum.  All  magnified.- After  Pfeffer.  branches  (Fig.  275).  The 

sporangia  are  more  or  less  globose  bodies,  which  are  short-stalked 
or  sessile  ;  they  contain  large  numbers  of  email  spores,  which  escape 
by  an  apical  slit  in  the  sporangium. 

*  J.  Fankhauser  :  "  Ueber  den  Vorkeini  von  Lycopodium,"  in  Botai- 
iache  Zeitung,  1873,  No.  1. 


SELAGINELLJ8. 


385 


Four  genera  belong  to  this  order,  viz.  ,  Lycopodium,  which  is  common 
in  the  wooded  portions  of  the  United  States  ;  Psilotum,  found  in 
Florida  ;  Tmesipteris  and  Phylloglossum,  of  Australia.  The  species 
number  from  sixty  to  seventy,  of  which  about  fifty  belong  to  the  genus 
Lycopodium. 

The  spores  of  Lycopodium  clavatum  are  gathered  in  Europe  and 
sold  for  various  minor  uses.  Many  species  have  a  high  ornamental 
value. 

This  order  was  represented  in  the  Devonian  by  species  of  Arctopo- 
dium.  In  the  Carboniferous  the  genus  Lycopodium  first  appeared. 

The  closely  related  extinct  order  Lepidodendreae  first  appeared  in  the 
Devonian,  in  which  it  was  represented  by  two  known  species  of  Lepi- 
dodendron  ;  in  the  Carboniferous  this  genus  was  represented  by  sixty  or 
more  species,  many  of  gi- 
gantic size,  and  the  order 
by  many  other  genera  —  e.g., 
Lepidophloios,  Lepidostro- 
bus,  Halonia,  etc.  In  the 
Permian  this  order  became 
extinct. 

Another  order—  the  Sigil- 
larieae  —  waa  represented  by 
many  species  of  Sigillaria 

in  the  Carboniferous  period. 

£,  .  Fig.  277  —  /.,  two  young  plants  of  Selagmelln 

Like  the  preceding,  this  or-    JUar-tthxii  growing  from  the  same  spore  ;  at  the 


,               -  - 

inrt    in  the  top  of  the  spore  may  be  seen  the  projecting  pro- 

16  thallium,  ;>.    //.,  a  young  plant  drawn  out  of  the 
spore,  showing  the  foot,  f,  on  the  left  below,  and 

o-iTi  «>11«>  the  y°UI1£  root.  r<  on  the  ri2llt-     m-   a  y°ung 

gmellee.—  plant  whwe  ,irst  lwlve8  (cotyledons)  have  been  re- 

The  prothallia  are  dioecious,  moved,  leaving  only  their  stipules  s;  between  the 

m,              ,  .  ,     ,       ,        -  latter  is  seen  the  dichotonKHuly  mvl&atgpwnctum 

Those  which  develop  from  vegetaUords;  p,  the  protlmlliiiin  Isolated  from  the 


Permian. 
Oi-rior 

Order 


the  macroepores  consist  of  a    spore.    /.  x 


protl 
//.  x  3;  ///.  X  30.—  After  Hoi- 

concavo-convex  many-celled 
structure,  which  develops  upon,  and  has  its  concave  side  applied  to,  the 
convex  surface  of  the  spore.  Upon  its  convex  surface,  which  protrudes 
through  the  ruptured  wall  of  the  spore,  are  a  few  root-hairs  and  many 
deeply  sunken  archegonia  (Fig.  276,  1,  2,  3).  The  microspores  develop 
only  the  smallest  rudiments  of  prothallia.  In  germination  a  single 
cell  (v,  Fig.  276,  D)  is  first  of  all  cut  off  ;  this  undergoes  no  further 
change,  and  is  doubtless  to  be  regarded  as  the  prothallium.  The  re- 
mainder of  the  spore  becomes  divided  in  a  regular  way  into  a  few 
large  primordial  cells  (Fig.  276,  A),  and  from  these  great  numbers  of 
sperm-cells  are  produced  (Fig.  276,  D). 

After  fertilization  the  germ-cell  divides  at  right  angles  to  the  axis 
of  the  archegonium  (Fig.  276,  3)  ;  from  the  upper  cell  so  formed  a 
suspensor  is  developed  (Fig.  276,  1),  while  the  lower  develops  into  the 
embryo.  The  embryo,  by  its  rapid  growth,  comes  eventually  to  occupy 


386 


BOTANY. 


the  cavity  of  the  spore  itself,  in  which,  by  bending  upon  itself,  it  lies 
at  right  angles  to  the  axis  of  the  archegonium.  The  new  plantlet 
bears  some  resemblance  to  the  embryo  in  the  Dicotyledons  ;  it  has  an 
elongated  stem,  bearing  at  its  summit  two  small  leaves  (cotyledons), 
having  between  them  a  growing  bud  (plumule) ;  at  the  lower  end  of 

the  stem  there  is  a  rudimentary 
root,  and  the  structure  known 
as  the  foot,  which  is  common  to 
all  Pteridophytes  (Fig.  277,  //.). 
The  young  plant  grows  from 
the  spore  with  its  cotyledons  fore- 
most (Fig.  277,  /.  and  777.) ;  this 
is  only  possible  by  the  great 
bending  of  the  embryo  upon 
itself,  for  at  first  its  cotyledon- 
ary  extremity  points  directly  to- 
ward the  centre  of  the  spore — 
i.e.,  away  from  the  opening  in 
the  spore-wall.  Usually  but  one 
plantlet  grows  from  each  pro- 
thallium  but  occasionally  two  or 
more  may  be  developed  (Fig. 
277,  7.) 

The  adult  plant  of  the  asex- 
ual generation  is  densely  leafy 
throughout.  The  leaves  are 
small,  moss  like,  and  are  gen- 
erally placed  in  four  rows,  of 
which  two  opposite  ones  are 
composed  of  large  leaves,  and 
the  two  intermediate  ones  of 
small  leaves.  Each  leaf  has  a 
small  scale-like  body,  the,  ligule, 
on  its  upper  surface  at  its  base. 
The  sporangia  occur  singly  in 
the  axils  of  certain  leaves,  gen- 
Fig.  278-J,  a  fertile  branch  of  Selaginella  erally  in  those  which  form  the 
nnri/iiiH'iui,  \\ith  the  quadrangular  spore-  .  .  .  ..  „  _. 

bearing  spike  at  the  apex  ;  B,  vertical  sec-    narrower"  fruiting  spikes    (Fig. 

^ffi^^^^nTn^eTand  278'  ^  Macrosporangia,  con- 
the  macrosporangia  with  macrosporcs  on  taming  four  macrospores  in 
the  right.-,!  X  2  ;  B  X  15. -After  Sach*  eacn>  U8ual] y  Qccur  in  gome  d(jfi. 

nite  portion  of  the  spike,  as  nearer  the  base,  or  upon  one  side  (Fig. 
278,  B).  The  uiicrosporangia  contain  many  microspores,  and  usually 
also  occupy  definite  positions  in  the  spike. 

But  one  genus,  Selaginella,  is  known  in  this  order ;  it  includes  150 
species  of  mostly  delicate  plants,  which  are  mainly  tropical,  not  more 


ISOETE^E. 


387 


than  three  or  four  species  occurring  within  the  limits  of  the  United 
States.     Many  are  cultivated  as  ornaments. 

Order  Isoeteee,  the  Quill  worts.  The  prothallia  of  the  Isoeteae  are  dioe- 
cious, and  resemble  closely  those  of  Se/aginella.  The  macrospores  give 
rise  to  small  prothallia,  which  project  through  the  triangular  slit  in  the 
spore-wall,  and  bear  several  or  many  sunken  nrchegonia  (Fig.  279).  The 
microspores,  in  their  germination,  first  cut  off  a  small  cell  (v,  Fig.  280, 
A  to  C),  which,  as  in  Selaginella,  represents  the  prothallium  ;  the  re- 
mainder of  the  spore  contents  becomes  divided  into  four  cells  (the 
primordial  cells),  and  these  give  rise  to  the  sperm-cells  (Fig.  280,  A  to 


Fig.  279. — 1,  Longitndin  1  section  of  a  prothallium  of  Tsoetes  lacustris,  four  weeks 
after  sowing  the  spore  ;  ar.  an  arcbegoninm.  2,  a  por.ion  of  the  apex  of  a  prothal- 
lium cut  through  longi  udinally,  with  two  archegonia,  ai\  ar,  still  in  process  of  devel- 
opment ;  g,  ff,  the  germ-cells  of  the  archegonia.  3,  longitudinal  section  of  an  arche- 
goninm  ready  for  fertilization.  4,  longitudinal  section. of  a  fertilized  archegonium, 
showing  the  germ-cell  transversely  divided.  5,  a  section  similar  to  the  last  ;  in  the 
lower  cell  of  the  embryo-rudiment  preparation  for  division  has  been  made  by  the  ap- 
pearance of  two  nuclei.  1  x  40  ;  2  and  3  X  300  ;  4  and  5  X  400.— After  Hofmeister. 

C).  The  spermatozoids  are  elongated  and  provided  with  cilia  at  both 
ends  (Fig.  280, /). 

The  germ-cell,  after  fertilization,  undergoes  transverse  division 
(Fig.  279,  4  and  5),  as  in  Selaginella,  and  its  subsequent  development 
is  essentially  the  same. 

The  adult  plant  of  the  asexual  generation  consists  of  a  very  short, 
thick,  tuber-like  stem,  which  bears  numerous  long,  narrow,  grass-like 
leaves,  which  are  sheathing  at  the  base.  There  are  also  numerous 
roots.  The  sporangia  are  produced  in  grooves  on  the  inner  side  of  the 
bases  of  the  leaves  ;  those  attached  to  the  outer  leaves  contain  macro- 


388 


BOTANY. 


spores,  while  the  interior  ones  contain  microspores.     Both  macrospcrea 
and  microspores  are  produced  in  great  numbers  in  the  sporangia. 

The  Quillworts  are  for  the  most  part  aquatic  plants  ;  they  are  found 
chiefly   in  the  north  temperate  and  warm  regions.      The  species,  of 


Pig.  280. — Germination  of  the  microspores  of  Isoetes  lacustris.  A ,  a  microapore, 
Bide  view.  S,  the  same,  ventral  view  ;  the  ppore  contents  have  divided  into  a  few 
cells,  of  which  v  in  each  figure  represents  the  rudimentary  prothiillium  ;  ^  ft  are  the 
ventral,  and  rf  <?  the  dorsal  cells.  C,  a  side  view  of  microstore  ;  the  four  cells,  ^;  £ 
it  d,  have  disappeared,  and  spermatozoids  have  formed.  D,  ventral  view  of  C\  a  to 
/,  development  of  spermatozoids.  e  and/  X  700,  the  others  x  580.— After  Millardet. 

which  there  are  probably  a  dozen  or  more,  all  belong  to  the  single 
genus  Tsoetes;  we  have  representatives  of  eight  or  ten  withiu   the 
United  States. 
Two  species  of  Isoetes  occur  as  fossils  in  the  Tertiary  (Miocene). 


CHAPTER    XX. 

PHANEROGAMIA. 
§  I.   GENERAL  CHARACTERS. 

496. — In  this  Division  the  alternation  of  generations 
which  is  so  well  marked  in  Bryophytes  and  in  most  Pterido- 
phytes  disappears.  We  have  seen  that  in  the  higher  Filicinae 
and  Lycopodinae  there  is  a  great  reduction  in  the  size  and 
importance  of  the  prothalliuin  (the  sexual  generation)  ;  in 
EquisetacecB  and  Filices  it  is  a  large  growth,  which  soon  be- 
comes entirely  independent  of  the  spore  from  which  it  origi- 
nates ;  in  OphioglossacecB  and  LycopodiacecB  it  is  of  consid- 
erable size,  but  it  is  less  capable  of  leading  an  independent 
existence ;  in  Rhizocarpece  and  SelaginellcB  it  is  reduced  to  a 
small  outgrowth  of  the  spore  ;  and  in  IsoetecB  the  reduction 
is  still  greater,  the  small  prothallium  being  little  more  than 
the  transformed  spore  contents. 

With  the  decrease  in  the  structural  importance  of  the 
prothallium  in  these  orders  of  the  Pteridophyta,  there  is  a 
noticeable  increase  in  the  differentiation  of  the  spore  before 
its  separation  from  the  parent  plant ;  thus  in  the  three  last- 
named  orders  the  spores  have  differentiated  into  (1)  small 
ones,  microspores.which  are  strictly  male  as  to  their  functions, 
and  (2)  larger  ones,  macrospores,  which  are  as  strictly  female. 

496. — In  the  Phanerogamia  the  changes  begun  in  the 
Pteridophyta  proceed  a  step  further.  The  differentiation 
into  male  and  female  organs  of  reproduction  is  carried  back 
far  beyond  the  formation  of  the  microspores  (pollen  grains) 
and  macrospores  (embryo  sacs)  ;  the  macrospore  does  not 
sever  its  connection  with  the  parent  plant,  but  continues  to 
be  nourished  by  it  until  after  the  embryo  is  formed ;  and  as 


390  BOTANY. 

a  consequence  of  its  maintaining  its  structural  connection 
with  the  parent  plant,  the  prothallium  (endosperm)  is  but 
feebly  developed.  The  prothallium  is  essentially,  as  to  its 
function,  a  nourishing  structure,  which  is  rendered  necessary 
in  the  Pteridophytes  by  the  fact  that  the  reproductive  bodies 
separate  from  the  parent  plant  before  they  are  ready  for  fer- 
tilization ;  and  just  as  this  separation  is  delayed,  or,  in  other 
words,  just  as  the  parent  plant  beskws  more  care  upon  the 
bodies  which  are  to  give  rise  to  the  embryo,  so  the  prothal- 
lium is  less  necessary,  and,  being  less  necessary,  is  less  de- 
veloped. Thus  we  find  a  much  smaller  prothallium  in  the 
heterosporous  orders  of  Pteridophytes  than  in  the  isosporous 
ones,  and  in  Phanerogams,  where  parental  care  extends  until 
after  the  formation  of  the  embryo,  there  is  generally  only 
the  smallest  rudiment  of  a  prothallium. 

497. — The  leafy  plant  (which  corresponds  to  the  asexual 
generation  of  the  Pteridophytes)  produces  two  kinds  of  re- 
productive cells,  viz.,  pollen  grains  and  embryo  sacs,  the 
homologues  respectively  of  microspores  and  macrospores. 
The  pollen  grains  are  for  the  most  part  single  cells,  which 
develop  from  mother-cells  in  the  interior  of  phyllome  struc- 
tures (modified  leaves) ;  they  soon  become  free,  and  are  then 
more  or  less  spherical  in  shape  ;  they  have  two  coats,  an  outer 
thick  one,  the  extine,  and  a  delicate  inner  one,  \he  intine, 
and  they  contain  a  granular  protoplasm,  in  which  oil  drops 
and  starch  granules  generally  occur.  The  embryo  sacs  are 
thin-walled  cells  which  arise  axially  in  the  ovules,  structures 
which  appear  to  be  homologous  to  the  macrosporangia  of 
Pteridophytes  ;  they  do  not  become  free,  but  continue  to  be 
m  organic  connection  with  the  cells  of  the  surrounding  tis- 
sues. Each  embryo  sac  develops  in  its  interior  a  larger  or 
smaller  mass  of  cells,  the  endosperm,  which  is  the  homo- 
logue  of  the  prothallium,  and  in  which  nourishing  matters 
are  deposited ;  it  also  develops  one  or  more  germ-cells,  the 
homologues  of  the  germ-cells  of  the  archegonia  in  Pterido- 
phytes. 

498. — The  portions  of  the  plant-body  which  produce  pol- 
len grains  and  embryo  sacs  are  in  general  considerably  modi- 
fied ;  thus  the  axis  is  generally  short,  the  leaves  delicate  or 


PHANEROGAMIA.  391 

otherwise  different  from  foliage  leaves,  and  containing  little 
or  no  chlorophyll  ;  they  are  usually  of  some  other  color  than 
green,  from  the  presence  of  soluble  coloring-matters  in  their 
cells.  These  modified  parts,  together  with  the  organs  more 
immediately  connected  with  the  male  and  female  reproduc- 
tive cells,  constitute  what  is  known  as  the  flower. 

499. — The  ovule,  in  its  development,  becomes  surrounded 
by  one  or  two  thin  cellular  coats,  which  grow  from  its  base, 
and  almost  completely  enclose  it,  a  little  orifice  only,  the 
micropyle,  being  left  at  its  apex.  In  the  lower  Phanero- 
gamia  (the  Gymnosperms)  the  ovule  enclosed  in  its  single 
(rarely  double)  coat  is  otherwise  naked,  while  in  the  higher 
classes — viz.,  the  Monocotyledons  and  Dicotyledons — it  is  en- 
closed within  the  cavity  of  the  ovary,  a  phyllome  structure, 
or,  as  it  is  commonly  described,  a  modified  leaf,  which  is 
folded  involutely  so  as  to  form  a  cavity. 

500. — In  the  fertilization  of  the  germ-cell  there  are  no 
spermutozoids  developed ;  instead  of  producing  these,  the 
pollen  grain  develops  a  long  slender  tube,  the  pollen  tube, 
which  penetrates  the  tissue  of  the  ovule,  and  comes  in  con- 
tact with  the  germ-cell  in  the  embryo  sac.  The  result  of 
fertilization  is  always  the  formation  of  a  suspensor  (some- 
times called  the  pro-embryo)  essentially  like  that  in  the 
Selaginellm  and  Isoetece,  and,  at  the  lower  end  of  this,  an 
embryo,  consisting  of  a  short  stem,  bearing  generally  one  or 
more  rudimentary  leaves  (cotyledons)  at  one  extremity,  and 
a  rudimentary  root  at  the  other.  The  embryo  grows  at  the 
expense  of  the  endosperm,  upon  which  it  gradually  en- 
croaches, and  in  many  orders  entirely  displaces.  "While  the 
embryo  is  forming,  the  ovule  becomes  greatly  enlarged,  and 
its  outer  coat  generally  much  thickened  and  hardened  ;  it  is 
now  called  the  seed,  and  soon  separates  at  its  base  from  the 
parent  plant. 

501. — After  a  longer  or  shorter  period  of  rest  the  seed 
germinates,  the  root  and  stem  elongate,  and  the  former 
pushes  out  through  the  micropyle  ;  in  those  seeds  in  which 
much  of  the  endosperm  remains,*  or  in  which  the  cotyle- 

*  Seeds  which  contain  endosperm  are,  in  the  ordinary  descriptive 


392  BOTANY. 

dons  are  greatly  thickened,  the  latter  remain  for  some  time 
inside  of  the  seed  ;  in  other  cases,  however,  they  soon  with- 
draw themselves,  and  become  expanded  as  the  first  leaves 
of  the  plantlet.  The  young  plant  is  quite  simple  at  first, 
but,  with  the  development  of  each  succeeding  internode,  it 
becomes  more  like  the  adult  plant. 

502. — The  three  tissue  systems  are  generally  well  de- 
veloped in  Phanerogamia.  The  epidermis  is  copiously  sup- 
plied with  stomata,  and  itself  consists  of  one  or  (rarely)  more 
layers  of  cells,  whose  external  walls  are  generally  somewhat 
thickened,  and  whose  cell  contents  rarely  contain  chloro- 
phyll. Trichomes  of  various  forms  are  abundantly  de- 
veloped. The  fibro-vascular  bundles  are  of  the  form  called 
by  De  Bary  collateral  bundles,  the  only  exception  being  the 
first  formed  one  in  the  root,  which  is  of  the  radial  type. 
The  bundles  are  symmetrically  arranged  in  the  stem,  through 
which  they  pass  vertically  parallel  to  each  other.  They  are 
mostly  common — i.e.,  they  extend  from  the  leaves  into  the 
stem  ;  but  some  are  strictly  cauline — i.e.,  they  are  found 
only  in  the  stems  and  have  no  connection  with  the  leaves. 
All  the  kinds  of  tissues,  with  the  exception  of  collenchyma, 
may  occur  in  the  bundles  ;  but  they  are  HIM  inly  made  up  of 
tracheary,  sieve,  and  fibrous  tissues.  In  the  larger  perennials, 
as  the  trees,  the  great  mass  of  tissue  in  the  woody  stems  is 
principally  made  up  of  the  tracheary  and  fibrous  tissues  of 
the  fibro-vascular  bundles.  In  succulent  plants,  especially 
those  growing  in  water,  the  bundles  are  usually  smaller  and 
more  simple,  being  sometimes  reduced  to  a  thread  of  trache- 
ary or  sieve  tissue. 

In  the  fundamental  tissues  parenchyma,  in  its  various 
forms,  is  by  far  the  most  common.  The  hypodermal  por- 
tions are  frequently  composed  of  collenchyma  or  scleren- 
chyma.  Laticiferous  tissue  is  common  in  the  fundamental 
system  of  certain  orders. 

503. — By  far  the  greater  number  of  Phanerogams  are 
chlorophyll-bearing  plants,  comparatively  few  only  being 


books,  said  to  be  albuminous,  while  those  in  which  it  is  wauling  are 

said  to  be  rxulbiiiuinous. 


OTMNOSPERM^.  393 

parasitic  or  saprophytic.  They  range  from  minute  plants 
one  or  two  centimetres  in  height,  and  living  but  a  few  days 
or  weeks,  to  enormous  trees,  which  continue  to  grow  for 
many  hundred  years,  and  which  attain  a  diameter  of  ten, 
and  a  height  of  one  hundred  metres. 

5O4. — The  Phanerogams  are  separable  into  two  classes, 
as  follows  :* 

Class  I.  Gymnospermae  (the  Archespermce  of  Strasbur- 
ger).  The  ovules  are  not  enclosed  in  an  ovary.  The  en- 
dosperm arises  before  fertilization,  and  forms  rudimentary 
archegonia  ("corpuscula"),  in  which  the  germ-cells  origi- 
nate. The  contents  of  the  pollen  grains  divide  before  the 
growth  of  the  pollen  tube,  forming  a  rudimentary  pro- 
thallium,  much  as  in  Selaginellce  and  Isoetece. 

Class  n.  Angiospermse  (the  Metaspermce  of  Strasburger). 
The  ovules  are  enclosed  in  an  ovary.  The  endosperm  is 
formed  after  fertilization.  The  contents  of  the  pollen  grain 
remain  undivided  before  and  during  the  growth  of  the  pollen 
tube. 

Sub-Class  Monocotyledones.— The  first  leaves  produced  by  the 
embryo  (the  cotyledons)  are  alternate  ;  the  endosperm  is  usually  large 
and  the  embryo  small. 

Sub-Class  Dicotyledones.— The  first  leaves  of  the  embryo  form  a 
whorl  of  two  (i.e.,  they  are  opposite);  the  endosperm  is  very  often 
rudimentary  or  entirely  wanting,  and  the  embryo  is  generally  large. 

§  II.   CLASS  GYMNOSPERMAE. 

505.— The  plants  of  this  class  have  solid  stems,  which 
bear  in  most  cases  small,  simple,  narrow  leaves  having  a 
parallel  venation.  The  xylem  portions  of  the  fibre-vascular 
bundles  of  the  stem  are  closely  compacted  into  a  single  dense 
woody  cylinder,  which  is  surrounded  by  a  looser  mass  of 
tissues,  the  so-called  bark,  composed  of  the  united  phloem 
portions  of  the  bundles.  The  woody  cylinder  increases  its 

*  This  is  essentially  Sachs'  arrangement,  in  his  "  Lehrbuch,"  4te 
Auf.  The  terms  Archespermae  (from  the  Greek  apxri,  beginning,  and 
therefore  properly  Archespermse,  instead  of  Archisperrnse)  and  Meta- 
spermae  (from  perd,  after  or  later)  are  those  proposed  by  Strasburger  : 
"  Die  Coniferen  und  die  Gnetaceen,"  1872,  p.  239. 


394 


BOTANY. 


diameter  centrifugally,  and  the  sheathing  envelope  of  bark 
centripetally,  by  the  growth  of  new  tissues  between  these 

two  portions. 

Gymnosperms  are  all  ter- 
restrial, chlorophyll-bear- 
ing plants  ;  none  are 
aquatic,  and  none  are  par- 
asitic. Most  of  them  are 
large  trees,  a  few  only 
being  shrubs  or  under- 
shrubs. 

506.  —  The  flowers  of 
Gymnosperms  are  much 
simpler  than  those  of  the 
remaining  Phanerogams. 

They  are  always  diclinous 

.  •*         ,  *,  ,     , 

—  I.e.,     the     male   ana    16- 

male  organs  are  in  differ- 


I.— A,  a  male  flower  of  Abie*  pfcflnrt- 
5,  bracts  ;  a,  stamens.    B.  pollen  grain  ; . 


-rafter  Sachs;  B  after  schacht. 


ent  flowers.     They  consist 
essentially  of  one  or  more 

variously  shaped  pollen-producing  organs  (stamens)  on  the 

one  hand,  and  naked  ovules  on  the  other  ;  both  kinds  of  or- 

gans are  in  most  cases  in  structural  connection  with  scale- 

like'bodies,  which  serve  as  acces- 

sory organs  of  reproduction. 
507.  —  The    male  flower    in 

Abies  pectinata  consists  of  an 

elongated  axis,  upon  which  are 

borne  a  large  number  of  spirally 

arranged  stamens  (a,  Fig.  281, 

A).    Each  stamen  is  morpholog- 

ically a  phyllome,  which  is  here 

modified  into  a  body  consisting 

Fig.  282.  -A  catkin  or  spike  of  the 

of   a   short   Stalk    (filament)  SUp-    male    flowers   of  Plim*  tylvtstris.— 
,-  11  /,  1  From  Le  Maont  and  Decuiane. 

porting  two  pollen  sacs  (the  an- 

ther). The  pollen  grains  are  developed  from  mother-cells, 
each  of  the  latter  giving  rise  to  four  grains.  The  pollen- 
mother-cells  themselves  arise  from  the  interior  parenchyma 
of  the  stamen  by  the  differentiation  and  enlargement  of  cer- 


QYMNOSPERM^l. 


395 


tain  cells.  Each  pollen  grain  is  at  first  a  single  cell,  but  by 
the  time  it  escapes  from  the  anther  it  is  a  several-celled  body, 
by  the  formation  of  partitions  within  its  cav- 
ity (q,  y,  Fig.  281,  B}.  The  daughter-cells 
thus  formed  arc  doubtless  the  homologues  of 
the  pro  thallium  of  the  higher  Pteridophytes. 
Each  mature  grain  has  a  double  wall,  of 
which  the  outer  one  (the  extine)  is  hard 
and  thick,  while 
the  inner  one  (in- 
fine)  is  thin  and 
delicate  (e  and  i, 

Fig.    281,  B}.       In    Decalsae." 

this  case  (as  indeed  is  common) 
there  are  two  vesicular  protru- 
sions of  the  extine  (bl,  Fig.  281, 
B),  which  give  the  grain  the  ap- 
pearance externally  of  being  three- 
celled. 

The  male  flowers  of  Pinus  syl- 
vestris  are   collected  into  catkins 

J-A  male  flower  of    °r  SPik«S    <*>    ?**).         ^    *** 

baceata,-  a,  th«  poiien  structurally   similar  to   those    de- 

Bacs.     B,  &  stamen,  seen    from  ,          " 

below,   c,  a  piece  of  a  foiia«e-  scribed  above.      The   stamens  are 

shoot,  e,  with  a  leaf,  b,  in  whose      ..  ,  ,  ,  ,  .     ,       . 

axil  is  a  scaly  jixis  (the  fe-  short  and  broad,  and  each  bears  on 
its  back  or  outer  surface  two  elon- 
gated pollen  sacs  (Fig.  283).  The 
pollen  grains  are  similar  to  those 

ovule;  m,  aril  ;  a;,  a  rudimentary  Q£   Abies 

axillary  ovule.    (|3P~  By  an  error 

of  the  engraver  the  hair  line  from          In  TttXUS  OaCCttta  the  male  flower 

a;  is  carried  about  1  mm.  too  high  _...,  .,      _       . 

in  the  figure.)   E,  longitudinal  differs  from  those  described  above 

section  of  an    older   ovule,  but          i     •      J.T.        t  £   Ai 

before  fertilization ;  i,  integu-  only  in  the  shape  of  the  stamens, 


which  are  peltate  and  lobed  (Fig. 
284,  B).     They  bear  attached   to 

emen  the    Under    SurfaCe    three    t0 

sfc*avlW8rA»"B  p°llen-s"cs>  which  contain 

figures  magnified.-After  Sachs.      globose  pollen  grains. 

These  examples  will  serve  to  illustrate  the  general  struc- 
ture of   the  male   flower,    which,   with  minor  variations, 


396 


BOTANY. 


is  in  nearly  all  the  class  essentially  like  the  ones  described. 
The  exceptions,  which  are  in  the  order  Gnetaceae,  will  be  de- 
scribed further  on.  It  may  be  pointed  out  here  that  in  pass- 
ing up  through  the  three  orders  of  the  class,  the  pollen  sacs, 
which  in  the  first  resemble  sporangia,  become  more  nearly 
like  the  anthers  of  the  Monocotyledons  and  Dicotyledons. 


FIG.  285. 


FIG   286. 


FIG.  287. 


Fig.  285. — A,  pollen  grains  of  Biota  vrientalis  before  their  escape  from  the  pollen 
sac  ;  7.,  fresh  ;  II.  and  ///.,  after  lying  in  water,  the  extine,  f,  having  been  stripped 
off  by  the  swelling  of  the  inline,  »  ;  the  protoplasmic  contents  are  seen  to  consist 
of  two  cells,  a  large  nucleated  one,  and  a  smaller  one.  S,  pollen  grains  of  Pinug 
pinaster,  before  their  escape  Irom  the  pollen  sac ;  f,  extine,  with  its  vesicular  protru- 
sions, bl;  IV.,  side  view;  V..  dorsal  view— the  protoplasmic  contents  are  divided 
similarly  to  those  in  A.  Magnified.— After  Sachs. 

Fis.  286. — A,  a  pollen  grain  of  Cufirestru-n  semperrirens,  showing  the  envelopes  (ex- 
tine  and  intine),  and  the  rudimentary  prothallium  as  a  small  cell  cut  off  from  the 
cell  contents.  B,  a  germinating  pollen  grain  ;  e,  the  fragments  of  the  ruptured  and 
exfoliated  extine  ;  i,  intine  ;  tp,  the  base  of  the  pollen  tube,  x  400.— After  Schaeht. 

Fig.  287. — Pollen  grains  of  Ceratozamia  lonyi  folia.  A,  before  permutation  ;  y, 
a  three-celled  body,  the  rudimentary  prothalliuni"  H.  a  germinating  pollen  grain  ;  e, 
the  ruptured  extine;  ps,  the  pollen  tube  ;  y,  rudimentary  prothalliuni.  Magnified. 
—After  Juriinyi. 

508. — The  pollen  grains,  like  the  male  flowers  themselves, 
are  essentially  alike,  although  differing  considerably  in  ex- 
ternal appearance.  The  vesicular  protrusions  of  the  ex- 
tine  (bl,  Figs.  285,  B,  and  281,  B),  which  are  common  in 
certain  genera  of  the  order  Conifera,  at  first  sight  hide  the 
close  similarity  which  exists  between  the  pollen  grains  in 
many  cases.  (Compare  A,  I.,  in  Fig.  285,  with  B,  IV.  of  the 


OTMNOSPERM^. 


397 


same  figure. )  In  all  cases,  unless  possibly  the  Gnetaceas  fur- 
nish some  exceptions,  the  pollen  grains  become  more  than  one- 
celled  before  the  formation  of  the  pollen  tube  (Figs.  281-5- 
6-7).  When  the  pollen  grains  germinate — i.e.,  send  out  their 
tubes — they  always  swell  up  and 
burst  the  extine  (which  slips  off 
in  the  Coniferae),  and  the  intine 
is  then  prolonged  into  a  tube, 
which  is  continuous  with  the 
cavity  of  the  grain,  and  into 
which  the  protoplasmic  con- 
tents pass  (Figs.  286  and  287). 
The  small  cells  take  no  active 
part  in  the  formation  of  the 
tube,  and  from  their  similarity, 
both  in  structure  and  function, 
to  the  small  cells  in  the  germi- 
nating microspores  of  the  Sel- 
aginellm,  there  can  be  no  doubt 
that  they  are  to  be  regarded 
as  constituting  a  rudimentary 
prothallium. 

509. — The  female  flower  is 
in  most  cases  a  similar  elon- 
gated axis,  upon  which  are  ar- 
ranged spirally  a  considerable 
number  of  phyllomes,  each 
bearing  two  or  more  naked  ov- 
ules. Thus  in  Abies  pectinata 
the  female  flower  is  the  young 
cone,  which  consists  of  an  axis 
(sp,  Fig.  288,  B}  bearing  nar-  ovulefi'«*<enlarged)-  #,  upper  pan  <>f 
row  bracts  (c),  which,  in  turn,  b^c^^hS^Sa^ 
develop  thick  scales  (s,  s)  upon  %*%£»%  ^K^JSS; 
their  upper  surface.  The  scales  scnacht. 

are  at  first  quite  small  (as  in  A),  and  it  is  only  as  the  cone 
becomes  older  that  they  grow  larger.  Each  scale  bears  on 
its  inner  face  two  inverted  ovules  (sk,  Fig.  288,  A). 

In  Pinus  sylvestris  the  structure  is  essentially  the  same  as 


Fig.  y».-A.  a  bract,  e,  detached 


BOTANY. 


Fig.  289.— A  ripe  cone  (female  flower)  of  Firing  gylwstris. 

Fig.  290.  -Partial  section  of  a  cone,  eg,  ag\  the  tcales ;  g,  the  seeds ;  em,  the 
embryo  in  the  seed. 

Fig.  291.— A  detached  scale  of  a  ripe  cone,  seen  from  above,  bearing  two  seeds. 
M,  rr.icropyle  ;  ch,  chalaza. 

Fig.  292.— A  detached  scale  of  a  young  cone,  Been  from  the  back,  showing  the  tri- 
angular bract.  Magnified. 

Fig.  293.— The  same  as  Fig.  291,  seen  from  the  front,  showing  the  two  ovules. 
Magnified. 


GYMNOSPERM^E.  399 

in  the  foregoing.  The  bract  is  smaller,  however,  and  the 
scale  attached  to  it  soon  becomes  very  large,  thick,  and 
woody  (Figs.  289,  290,  and  291).  The  bract  and  scale  in 
this  case  have  nearly  the  same  relative  proportions  when 
young  as  they  have  in  the  mature 
cone  of  Abies  pectinata.  (Com- 
pare Fig.  288  with  Figs.  292-3.) 
In  other  cases,  as  in  Callitris 
quadrivalvis,  the  axis  is  short, 
and  the  phyllomes  (d,  Fig.  294) 
which  bear  the  ovules  are  only 
four  in  number  (Fig.  294,  Ks, 

+Vio   nviiloa^        Tn    TnviiQ  "hnrftitn       ^S-  294- — Female  flower  of  Calli- 
tlie   OVUleS j.       In    laXUS  baCUlta    trisqwadrivalvis.    d,d,  decussating 

the  flower  is  still  more  simple.   ^Pnifled/  -After  bach's'  8ix  ovule8' 

It  appears  in  the  axil  of  a  foliage 

leaf,  and  is  a  scaly  axis,  resembling  a  small  cone  (C,  Fig. 

284).     The  lower  scales  do  not,  however,  bear  ovules,  and 

at  the  top  of  the  axis  is  a  single  naked  ovule  (D  and  E,  Fig. 

284).     This  simplicity  is  carried  a  step  further  in  Ginkgo, 

where  the  female  flowers  are  merely  naked  axes,  which  bear 

no  bracts  or  scales, 
and  produce  but  two 
ovules  at  their  sum- 
mits (Fig.  295,  sk)* 
The  female  flower 
of  Cycas  revoluta  is 
a  rosette  of  phyl- 
lomes, which  bear 
some  resemblance  to 
foliage  leaves,  being, 
however,  smaller, 

Fig.  295.— A  shoot  of  Ginkgo  biloba.      sk.  ovules  bl'OWnisll,  and  hairy, 

in  pairs  at  the  ends*  of  naked  axes;  above  and  on  the  Ai,™-      fVia     1  ^ -or  Q  v 

right  are  shown   fragments    of   two   leaves,  which  Att«lg 

are  seeu  to  be  broad.    Nat.  size. -After  Sachs.  partg    Qf    t}iejr    mar_ 

gins  they  produce  a  number  of  spherical  naked  ovules  (sk, 

*  The  morphology  of  the  flowers  of  Ginkgo,  as  here  given,  is  by  no 
means  satisfactory.  Instead  of  the  ovules  being  borne  upon  naked 
axes,  it  is  probable  that  they  are  in  reality  upon  foliar  organs — i.e., 
either  modified  leaves,  somewhat  as  in  Cyca»,  or  upon  elongated  homo- 


400 


BOTANY. 


Fig.  29G).     These  structures,   which  may  be  called  carpel- 
lary  leaves,  show  their  relationship  to  ordinary  foliage  leaves 


Fig.  2%.— A  pinnate,  open  carpellary  leaf  of  Cycas  revoluta  (reduced  one  half).  /, 
nnaltered  pinnae;  nk,  young  ovules  replacing  the  lower  pinna; ;  xk',  fully  developed 
ovule.—  After  Sachs. 

in  having  pinnae  toward  their  summits  (/,  Fig.  296). 

The  examples  given  will  illustrate  the  general  structure  of 

lojrues  of  the  "  scales  "  of  Abies.     Either  interpretation  would  necessi- 
tate a  conniderable  change  in  the  systematic  arrangement  of  Taxinew. 


O  YMNOSPEEM^E. 


401 


the  female  flower  of  the  Gymnosperms.  The  only  consider- 
able departure  from  the  plan  of  the  flower,  as  here  given,  is 
found  in  the  order  Gfnetacea,  which  will  be  described  further 


on. 


510. — The  ovule  is  at  first  a  minute  protuberance   of 


B 


Fig.  297. — A,  longitudinal  section  of  an  ovule  of  Pinus  Larico,  taken  from  a 
cone  just  opened  ;  c,  the  coat  of  the  ovule,  in  section  ;  ov,  the  body  or  "nucleus"  of 
the  ovule  ;  this  includes  all  the  figure  which  is  filled  out.  showing  the  cells  ;  em,  thu 
young  embryo  sac.  B,  a  similar  section  of  the  ovule  of  Abies  pectinata,  after  the  en- 
trance of  the  pollen  tube?,  pt,  into  the  corpuecula,  cp,  cp  ;  ov,  the  body  or  "  nucleus'1 
of  thu  ovule— the  upper  portion  is  cut  away  (the  cells  composing  its  tissue  are  not 
shown);  w,  the  wall  of  the  embryo  sac;  en,  endosperm  in  the  enlarged  embryo  sac  ; 
en,  cp,  two  corpuscula ;  n,  the  neck  of  one  of  the  corpuscula ;  pr,  the  first  cells  of 
the  pro-embryo.  A  X  150  ;  B  x  30.— A  after  Hofmeister  ;  £  after  Strasburger. 

small-celled  tissue  ;  a  little  later  a  ring  grows  out  from  its 
base,  and  rises  as  a  sheath  (the  integument  or  coat),  which 
finally  more  or  less  completely  closes  it  in  ;  in  a  few  cases  a 
second  integument  forms  outside  of  the  first  one.  At  a  cer- 
tain stage  of  its  growth  one  of  the  interior  cells  of  the  ovule 
grows  larger  than  the  others,  and  becomes  the  embryo  sac 
(em,  Fig.  297,  A) ;  in  it  there  arise  numbers  of  free  cells, 


402 


BOTANY. 


which  multiply  by  fission,  and  eventually  unite  into  a  con- 
tinuous tissue  (in  reality  a  false  tissue),  the  endosperm  (en, 
Fig.  297,  B).  In  this  mass  of  endosperm  cells  several  near 
the  micropylar  end  grow  larger  than  the  surrounding  ones, 
and  become  filled  with  granular  protoplasm.  These  are  the 

corpuscula  of  Brown,  the 
archeyonia  of  Sachs,  or 
the  secondary  embryo  sacs 
of  Henfrey  (cp,  cp,  Fig. 
297,  B}.  In  some  cases 
they  are  placed  singly  at 
short  distances  from  each 
other,  while  in  others  they 
are  clustered  together 
(1  and  2,  Fig.  298).  Each 
corpusculum  is  at  first  a 
single  cell,  but  when  fully 
developed  it  consists  of  an 
elongated  cell,  the  germ- 
cell  proper,  and,  in  many 
cases  at  least,  one  or  more 
neck-cells,  the  whole  sunk- 
en deeply  into  the  sub- 
Fig.  298  -1.  Three  corpnecula.  cp,  of  Juni-  stance  of  the  endosperm. 
erus  rrminiuiiia,  close  together,  and  seen  in  a  „.  ,  .  ,  ,  , r  ., 

ngitudinal  section  of  the  ovule  ;  rf,  the  first  lllC  neck  IS  formed  by  the 
suspcnsor  cells  of  two  fertilized  corpuscnla —         , ,  •  a      e  .c 

at  the  tipper  end  of  the  corpuscula  are  shown  Cutting  Off   01  a  portion  OI 

ISK  the  original  cell  of  the  cor- 


endosperm  in  enlarged  embryo  sac  ;  <?',  portion  .      - 

of  endosperm  broken  up :    cp.  three  corpus-  f  Orm    a   Vertical     TOW 

cula,  from  the  lower  ends  of  which  the  BUS 

fore,  v.  grow 

3  X  100  ;  4  X 


v.  grow  ;  p,  pollen  tube.     1  and  2  X 
;  50.-After  Hofmeieter. 


?•  it  remains  single,  while  in 

cleus,",*;/:,  of  the  ovule,  shown  in  outline ;  «,  others    it    divides    SO    as   to 

and 

lj  in  others  a  four-  or  even 
eight  -  celled  transverse 
plane  (see  Fig.  298,  1)  ;  the  latter  arrangement  has  been 
termed  a  rosette. 

511. — If  we  now  review  the  structure  of  the  ovule  its  ho- 
mologies  can  be  readily  made  out.  The  ovule  itself  plainly 
corresponds  to  the  macrosporangium  of  the  higher  Pterido- 
phytes,  and  the  embryo  sac  is  to  be  regarded  as  the  homo- 


OYMNOSPERM^E. 


403 


logue  of  a  macrospore,  which  here  is  not  freed  from  the 
parent  plant.  The  endosperm  clearly  bears  the  same  rela- 
tion to  the  embryo  sac  as  the  prothallium  of  Isoetes  does  to 
the  macrospore ;  and  the  corpuscula  are  slightly  modified 
archegonia.  In  some  corpuscula  the  resemblance  to  arche- 
gonia  is  very  marked,  the  germ-cell  below  being  surmounted 
by  a  short  neck ;  Strasburger  has  even  discovered  a  rudi- 
mentary axial-cell,  thus  completing  the  correspondence  of 
these  organs  to  those  of  the 
higher  Pteridophytes. 

512. — Fertilization  is  effect- 
ed by  means  of  the  pollen, 
which  comes  in  contact  with 
the  apex  of  the  ovule.  It  is 
transported  from  the  male 
flowers  mostly  by  the  wind, 
which  accounts  for  the  im- 
mense quantity  produced. 
When  the  ovule  has  reached  the 
proper  stage  the  micropyle  is 
filled  with  a  fluid,  which,  dry- 
ing,  carries  the  adherent  pollen  J^«¥SSZ*™Z£t$w£ 
grains  into  contact  with  the  ^.J^pg^^^J; 
apex  of  the  ovule  body,  where  ££  '^n^.legJ8j^fwt.^  °e^8;  l^6.  |™" 
they  germinate  and  form  pol-  two  corpuscula  shown  ailed  with  pro- 

,    ,  ,-.       -.  toplasm ;  A,  the  neck  cell  of  one  cor- 

len  tubes  ;  the  latter  penetrate  puscuium ;  p,  two  pollen  grains  ap- 

tlie  Soft  tissue  Of  the  OVule  and    mtoVMch'the^have  eent°twoe  pboUen 

eventually  reach  the  corpus-  tube8'  '•'— After  FrantL 
cula  (Fig.  299).  In  those  cases  where  the  corpuscula  are 
separated  from  one  another  each  pollen  tube  comes  in  con- 
tact with  only  one  corpusculum  (Figs.  297,  B,  and  299)  ;  but 
when  the  corpuscula  are  close  together  a  single  pollen  tube 
may  come  in  contact  with  all  of  them  (Fig.  298,  1  and  2). 
The  union  of  the  protoplasm  of  the  pollen  tube  with  that  of 
the  germ-cell  appears  to  take  place  by  diffusion  through  the 
wall  of  the  former,  as  no  openings  in  it  have  been  discovered. 
After  fertilization  the  protoplasm  in  the  germ-cell  becomes 
more  turbid  and  granular,  and  soon  at  the  base  a  transverse 
partition  is  formed,  cutting  off  a  cell,  which  is  the  rudiment 


404  BOTANY. 

of  the  suspensor.  By  the  growth  and  fission  of  this  first 
cell  an  elongated  tortuous  filament — the  suspensor — is  at 
length  formed,  which  develops  at  its  lower  extremity  a  rudi- 
mentary embryo  (eb,  Fig.  298,  3).  Sometimes  each  suspen- 
sor splits  into  several  parallel  ones,  each  of  which  forms  a 
rudimentary  embryo,  but  in  such  cases  it  rarely  happens 
that  more  than  one  continues  to  grow.  While  the  embryo 
is  growing  the  ovule  increases  greatly  in  size,  and  its  coat 
becomes  hardened  or  otherwise  modified.  Internally,  the 
endosperm  in  the  embryo  sac  grows  still  more  rapidly,  and 
finally  entirely  replaces  the  other  tissues  of  the  ovule.  The 
endosperm-cells  at  this  stage  are  filled  with  nutrient  materials 
for  the  support  of  the  embryo. 

513. — The  stem  of  the  embryo  develops  upon  the  lower 
end  of  the  suspensor  as  a  very  short  cylindrical  mass ;  the 
end  opposite  to  the  suspensor  is  a  growing  point  (punctum 
vegetationis),  and  this  produces  two  or  more  cotyledons  as 
lateral  members  ;  lastly,  upon  the  end  of  the  axis  next  to, 
and  under,  the  suspensor  a  rudimentary  root  forms,  covered 
with  a  few-celled  root  cap.  The  fully  formed  embryo  has 
thus,  (1)  an  axis  (called  also  the  hypocotyledonary  stem,  cau- 
licle,  and  erroneously  the  radicle)  ;  (2)  the  cotyledons  ;  (3)  a 
growing  point  above  the  whorl  of  cotyledons  (called  also  the 
plumule) ;  (4)  a  rudimentary  root,  which  is  the  true  radicle, 
and  to  which  alone  the  term  should  be  applied. 

514. — When  the  ovule  and  its  contained  embryo  reach  the 
stage  last  described  above  they  constitute  the  Seed.  The 
growth  of  the  embryo  is  suspended,  and  the  tissues  which 
maintained  organic  connection  between  the  ovule  and  the 
parent  plant  are  absorbed,  thus  setting  the  seed  free.  Under 
proper  conditions  the  suspension  of  the  growth  of  the  em- 
bryo may  be  prolonged  for  some  years  without  the  loss  of 
its  power  of  resuming  it  again  ;  this  latter,  or  the  germina- 
tion of  the  seed,  takes  place  whenever  the  necessary  amounts 
of  heat  and  moisture  are  present.  The  first  stage  in  germina- 
tion is  the  swelling  of  the  endosperm,  which  ruptures  the 
hardened  integument  (testa) ;  this  is  followed  by  the  rapid 
elongation  of  the  axis  (caulicle)  of  the  embryo,  by  which  (In- 
growing root  is  pushed  out  (Fig.  300,  II.} ;  the  latter  forms 


O  YMNOSPERMJE. 


405 


the  first  root  of  the 
its  whole  root  sys- 
tem. The  cotyle- 
dons having  thus 
far  been  in  contact 
with  the  e  n  d  o  - 
sperm,  which  fur- 
nished them  with 
nourishment,  now 
elongate  and  push 
out  their  bases,  and 
in  some  cases  even- 
tually withdraw 
themselves  entirely 
from  the  seed  coat 
(Fig.  300,  ///.). 
The  apex  of  the 
axis  (plumule)  be- 
gins a  rapid  growth, 
which  gives  rise  to 
a  leafy  stem  resem- 
bling that  of  the 
parent  plant,  al- 
though usually 
somewhat  simpler. 

515.— The  tis- 
sues of  the  Gymno- 
sperms  are  individ- 
ually but  little  high- 
er than  those  of  the 
Pteridophytes,  but 
in  the  mode  of  their 
aggregation  they 
present  great  and 
important  differ- 
ences, in  this  latter 
respect  bearing  a 
close  resemblance  to 
the  tissues  of  the 
Dicotyledons  among 


new  plant,  and  eventually  gives  rise  to 


Fig.  300.— Seeds  of  Pinus  Pinea  in  different  stages  of 
germination.  /.,  ripe  seed  in  longitudinal  section ;  «, 
the  seed  coat ;  e,  endosperm  ;  w,  the  hypocotyledonary 
axis  of  embryo  ;  c.  cotyledons  ;  y,  the  micropylar  end 
of  the  seed,  with  the  root  of  the  embryo  directed  to- 
wards it.  If. ,  //.,  four  views  of  the  beginning  of  ger- 
mination ;  A,  external  view  ;  B,  with  half  of  the  seed 
coat  removed ;  C\  in  longitudinal  section ;  D,  in 
transverse  section  :  *-,  seed  coat ;  •/•,  red  membrane  lin- 
ing the  seed  coat ;  e.  endosperm  :  c,  cotyledons  ;  w, 
root ;  a?,  ruptured  embryo  sac.  ///.,  germination  com- 


plete, the  cotyledons,  c,  unfolding,  and  the  hypoctyle- 
donary  stem,  lie,  elongating  ;  w,  the  i     ' 
oping  lateral  roots,  w'.— After  Sachs. 


• ;  w,  the  main  root,  devel- 


the  Angiosperms.    The  three  tissue  sys- 


406 


BOTANY. 


terns  are  well  defined,  and  include  most  of  the  tissues  de- 
scribed in  Chapter  VI.  (page  69  et  seq.). 

The  epidermal  system  consists  of  one  or  more  layers  of 
epidermal  cells,   which    are    frequently  much   thickened; 


Fig.  301.— Diagrammatic  cross-sections  of  the  stem  of  Gymnosperms.  A,  young 
stem  with  the  fibre-vascular  bundles,  /ft,  widely  separated  ;  p,  the  phloem  ;  x,  the 
xylcm  ;  fs,  tissues  of  the  fundamental  system  :  e,  epidermis.  li,  a  similar  section  of 
an  older  stem,  the  cambium  layer,  e,  extended  through  the  fundamental  system 
from  bundle  to  bundle.  C,  section  of  a  three-year-old  stem,  showing  the  manner  of 
increase  in  the  xylem  and  phloem  ;  pc,  primary  cortex  (phloem)  ;  gc,  secondary  cor- 
tex (phloem)  ;  c,  cambium  layer;  sw,  secondary  wood  (xylcm);  />«',  primary  wood 
(xylem) ;  p,  pith  ;  pi,  p2,  p3,  sol,  «2,  sc3,  corresponding  phloem  and  xylem  portions 
of  each  year's  growth  of  the  bundle. 

stomata  are  common,  and  in  general,  are  quite  regularly  dis- 
posed in  lines  ;  the  outer  surface  is  occasionally  covered  with 
well-developed  trichomes  ;  in  general,  however,  they  present 
themselves  as  rough  points,  which  give  a  harshness  to  the 


G  YMNOSPERM^E. 


407 


surface.     In  many  cases  oil  or  resin  receptacles  occur  in,  or 
immediately  beneath,  the  epidermis. 

516. — The  fibro- vascular  bundles  are  for  the  most  part 
of  the  collateral  form,  and  in  the  young  stem  they  are  ar- 
ranged so  as  to  form  an  inner  xylem  cylinder  ensheathed  by 
a  phloem  cylinder  (Fig.  301).  The  xylem  of  these  first- 
formed  bundles  is  composed  of  an  inner  mass  of  annular  and 
spiral  vessels,  which  gradually  pass  outwardly  into  tracheides. 
The  phloem  is  mostly  composed  of  an  outer  mass  of  bast 


Fig.  SOla.— Croas-gection  through  the  new  wood  (k-h),  cambhim  ( x  -  x ),  and  bark 
(b-b)  of  the  stem  of  Junlperus  commi/nis,  made  at  the  end  of  September,  m,  m,  me- 
dullary rays.  In  the  bark  are  shown  the  layers  of  bast  fibres,  b,  b,  b.  Magnified.— 
After  De  Bary. 

fibres,  which  is  bordered  internally  by  a  mass  of  sieve  tissue 
(latticed  or  cambiform  cells)  and  parenchyma.  Between  the 
xylem  and  the  phloem  a  layer  of  cells  always  remains  as  a 
meristem  tissue  ;  this  constitutes  the  cambium  layer  of  the 
bundles  (c,  Fig.  301,  B.,  and  x-X,  Fig.  301«). 

517. — The  increase  in  the  diameter  of  the  stem  takes 
place  by  the  multiplication  of  cells  in  the  cambism  layer  ; 
the  cambium  cells  undergo  longitudinal  fission  by  the  forma- 
tion of  partitions  at  right  angles  to  the  radii ;  these  new  cells 


408  BOTANY. 

are  developed  on  the  one  hand  into  tracheides,  which  com- 
pose the  secondary  wood,  and  on  the  other  into  parenchyma 
and  fibrous  tissue,  composing  the  secondary  cortex  (sw  and 
sc,  Fig.  301,  C).  There  always  remains  a  layer  of  meristem 
tissue  between  the  secondary  wood  and  cortex  thus  formed, 
so  that  the  next  year  an  additional  increase  is  made  again  in 
exactly  the  same  manner.  Thus  it  happens  that  the  new 
growth  takes  place  between  the  xylem  and  phloem  portions 
last  formed,  and  that  the  corresponding  xylem  and  phloem 
parts  of  any  year's  growth  come  at  last  to  be  separated  by 
the  similar  parts  of  all  the  subsequent  years'  growths  (fb, 
Fig.  301,  C). 

The  tracheides  are  much  elongated,  with  somewhat  taper- 
ing ends  ;  their  walls  are  thickened,  and  are  more  or  less 
copiously  supplied  with  bordered  pits.  (See  Fig.  15,  p.  25.) 

518. — The  fundamental  system  of  tissues  in  the  stem  be- 
comes divided  into  two  portions  by  the  development  of  the 
fibre-vascular  cylinder  described  above.  The  inner  portion, 
the  pith,  which  occupies  the  axis  of  the  stem,  is  composed  of 
parenchyma,  which  soon  loses  its  vitality,  and  persists  as  a 
mass  of  thin-walled  and  generally  empty  cells.  The  outer 
portion,  the  primary  cortex,  consists  of  parenchyma,  which 
is  usually  chlorophyll-bearing,  and  a  greater  or  less  amount 
of  sclerenchyma  or  collenchyma.  There  is  frequently  a  con- 
siderable development  of  cork  in  the  primary  cortex,  and 
not  rarely  the  whole  of  the  primary  cortex  undergoes  a 
corky  degeneration.  Between  the  fibro-vascular  bundles 
there  are  broader  or  narrower  plates  of  tissue,  composing  the 
so-called  medullary  rays,  which  in  the  young  stems  are 
parenchymatous,  but  in  older  ones  they  are  sclerenchyma- 
tous  (Fig.  301«,  m,  m).  In  that  portion  of  each  medullary 
ray  lying  between  the  cambium  layers  of  two  contiguous 
fibro-vascular  bundles  there  is  a  layer  of  meristem  tissue,  the 
cambium  of  the  medullary  rays,  or  the  inter-fascicular  cam- 
bium. As  this  is  continuous  with  the  cambium  of  the 
bundles,  there  is  thus  formed  a  cylinder  of  cambium,  sepa- 
rating not  only  the  fibro-vascular,  but  also  the  fundamental 
portions  of  the  stem,  into  two  parts  (B,  Fig.  301).  By  the 
formation  of  new  cells  by  fission  in  the  inter-fascicular  cam- 


GYMNOSPERM^K  409 

bium  at  the  time  of  activity  in  the  cambium  of  the  fibro- 
vascular  bundles,  there  is  an  annual  addition  made  to  the 
fundamental  tissues  of  the  stem  corresponding  to  the  addi- 
tion made  in  the  fibro-vascular  bundles. 

510. — By  this  internal  increase  of  tissues  in  the  stem  the 
epidermis  is  at  length  raptured,  and  the  primary  cortex  be- 
comes exposed,  and  eventually  broken  up  and  destroyed. 
The  phloem  portions  of  the  fibro- vascular  bundles,  and  the 
subsequent  external  additions  to  the  fundamental  tissues 
made  by  the  inter-fascicular  cambium,  constitute  what  is 
called  the  Bark  of  the  stem.  There  are  usually  in  it  corky 
developments,  which  often  very  considerably  change  the 
character  and  alter  the  relations  of  its  parts.  The  paren- 
chyma frequently  becomes  somewhat  sclerenchymatous,  while 
in  other  cases  it  undergoes  a  peculiar  degeneration. 

520. — Most  Gymnosperms  have  intercellular  canals  in 
their  stems,  either  in  the  fibro-vascular  or  the  fundamental 
portions  ;  these  contain  a  turpentine  in  which  is  dissolved  a 
resin.  * 

521. — There  are  three  quite  Avell-marked  orders  of  Gym- 
nosperms, which  may  be  separated  as  follows  : 

1.  Cycadese,  the  Cycads.    Stem  simple,  or  rarely  branched, 
not  resinous  ;  pith  large  ;  leaves  large,  pinnately  compound, 
crowded  upon  the  stem. 

2.  Conifer®,  the  Conifers.     Stem  branched,  usually  resin- 

*  The  distribution  of  these  canals  has  been  made  out  by  Van  Tieghem 
(Ann.  des  8ci.  Nat.,  1872)  to  be  as  follows  for  the  principal  genera  of 
Conifera  : 

1.  No  canals  in  root  or  stem—  Taxus. 

2.  Canals  in  the  stem  only. 

(a)  la  the  cortical  parenchyma — Taxodium,  Podocarpus,  Tor- 

reya,  Tsuga,  etc. 
(6)  In  the  pith  also— Ginkgo. 

3.  Canals  in  both  stem  and  root. 

In  the  cortical  parenchyma  of  the  stem— Cedrus,  Abies,  etc. 

(a)  In  the  xyleni  of  the  fibro-vascular  bundles  of  root  and 

stem— Pinus,  Larix,  Picea,  Pseudolarix. 
(6)  In  the  phloem  of  the  fibro-vascular  bundles  of  root  and 

stem—  Thuya,  Cuprewm,  TUnta,  Araucaria,  etc. 


410  BOTANY. 

ous ;   pith  slender  ;  leaves  small,  simple,  mostly  crowded 
upon  the  stem,  sometimes  scattered. 

3.  G-netaceae,  the  Joint-Firs.  Stem  branched,  not  resin- 
ous ;  pith  slender ;  leaves  small,  opposite,  upon  elongated 
internodes,  or  large  and  only  two  on  a  short,  thick  stem. 

Order  Cycadese.— The  Cycads  are  large  or  small  trees,  with  much 
the  general  appearance  of  the  palms  and  tree-ferns.  They  are  of  slow 
growth  and  are  long-lived  ;  the  stem  elongates  by  a  slowly  unfolding 
terminal  bud,  which  gives  rise  to  a  crown  of  widely-spreading  pinnate 
leaves,  which  are  constantly  renewed  above  as  they  die  and  fall  away 
below. 

Nine  genera  (Gycas,  Enccphalartos,  Macrozamia,  Zamia,  Ceratozamia, 
etc.),  and  from  fifty  to  sixty  species,  are  known  ;  they  are  all  tropical  or 
sub-tropical,  and  are  about  equally  distributed  in  both  the  Eastern  and 
Western  continents.  Three  species  occur  within  the  United  States  (in 
Florida),  viz.,  Zamia  integrifolid,  Z.  pumila,  Z.  Floridana. 

Many  species  contain  considerable  quantities  of  starch  in  their  thick 
stems  ;  from  this  a  kind  of  sago  is  made.  In  some  cases  the  seeds  also 
are  nutritious. 

Order  Coniferse.— The  Conifers  are  for  the  most  part  trees  of  a  con- 
siderable size,  with  branching,  spreading,  or  spiry  tops.  They  are 
generally  of  rapid  growth,  and  in  many  cases  attain  a  great  height  and 
diameter.  In  the  greater  number  of  species  the  leaves  are  persistent, 
and  the  trees,  consequently,  evergreen. 

The  order  contains  thirty-three  genera  and  about  three  hundred  spe- 
cies, which  are  distributed  mainly  in  the  cooler  climates  of  the  globe. 
Fifty  or  more  species  occur  within  the  limits  of  the  United  States. 

The  disposition  of  the  genera  may  be  understood  from  the  following 
arrangement,  which  is  essentially  that  of  Parlatore  in  De  Candolle's 
"  Prodromus" : 

Tribe  I.  Taxinece. — Flowers  dioacious  or  rarely  monoacious ; 
fruit  fleshy  ;  non-resinous  trees  or  shrubs. 

Gen.  Oinkgo  (Salisburia),  Phyllocladus,  Podocarpus,  Torreya,  Taxus, 
etc. 

The  seeds  of  Ginkgo  are  eaten  in  Japan  as  a  dessert.  Many  species 
furnish  valuable  timber,  which  is  generally  very  durable.  The  wood 
of  the  yew  (Taxus  baccata)  of  Europe  and  Asia  is  almost  indestructible 

Species  of  Podocarpus  in  Java,  Australia,  and  New  Zealand  attain  a 
great  height,  and  afford  good  timber  ;  allied  species  in  the  West  Indies 
and  South  America  are  equally  valuable. 

Oinkgo  is  now  planted  in  this  country  as  an  ornamental  tree. 

Tribe  II.  Abietinece. — Flowers  monoecious  or  direcious ;  fruit  a 
woody  cone  (excepting  in  Juniperus).  Kesinous  trees,  a  few  shrubs. 


CONIFERS.  411 

Sub-Tribe  I.  Cupressece.—Sc&les  of  the  cone  four  or  more,  decus- 
sately  opposite,  or  three  or  four  in  a  wliorl,  persistent.  Leaves  usu- 
ally scale-like,  persistent,  opposite  or  whorled. 

Gen.  Juniperus,  Cupressus,  Chamcucyparis,  Thuya,  Libocedrus,  Calli- 
tris,  etc. 

The  fleshy  cones  (the  so-called  berries)  of  Juniperus  communis  are 
used  in  medicine,  as  are  also  the  leaves  of  J.  SaUna  ;  from  the  former 
an  oil  is  obtained  by  distillation. 

The  wood  of  most  of  the  species  is  valuable. 

From  Juniperus  Virginiana  of  North  America  and  /.  Bermudiana 
of  the  Bermudas,  the  wood  is  obtained  for  making  lead  pencils. 

Cupressus  sempenirens  is  the  Cypress,  a  native  of  the  Levant  ;  its 
wood  is  nearly  indestructible.  C.  macrocarpa  is  the  beautiful  "Mon- 
terey Cypress  "  of  California. 

ChamcBcyparis  sphceroidea,  the  White  Cedar  of  the  Eastern  United 
States,  is  used  in  the  manufacture  of  pails,  tubs,  etc.  Several  allied 
species  from  Japan  are  cultivated  under  the  name  of  Betinospora. 

Thuya,  occidental™,  the  Arbor  Vitae  of  the  Eastern  United  States,  sup- 
plies enduring  posts,  etc.  ;  its  congener  of  California  and  Oregon  ( T. 
gigantea)  is  an  immense  tree  30  to  60  metres  (100-200  ft.)  high. 

Libocedrus  decurrens,  nearly  related  to  the  last  named,  is  another 
large  Californian  tree. 

Sub-Tribe  II.  Taxodiece.  —  Scales  of  the  cone  spirally  arranged 
(whorled  in  one  genus),  persistent.  Seeds  three  to  nine  upon  each 
scale.  Leaves  usually  linear,  arranged  spirally,  or  in  two  ranks. 

Gen.  Taxodium,  Sequoia,  Sciadopytis,  etc.  Taxodium  distichum,  the 
Bald  Cypress  of  the  Southern  United  States,  is  valuable  for  its  durable 
timber.  Sequoia  gigantea,  the  Giant  Redwood,  or  Big  Tree  of  Califor- 
nia, grows  only  on  the  western  slopes  of  the  Sierra  Nevada  Mountains. 
It  attains  a  height  of  more  than  100  metres  (300  ft.),  and  a  diameter  of 
6-10  metres  (20  to  30  ft.).  Its  wood  is  red  in  color,  and  very  durable.  8. 
sempermrens,  the  Redwood  of  the  Coast  Range  Mountains,  is  a  some- 
what smaller  tree  ;  its  durable  timber  is  much  used  for  making  shingles, 
weather-boarding,  fences,  etc.  Sciadopytis  wrticillata  and  Cryptomeria 
Japonica,  large  trees  of  China  and  Japan,  furnish  valuable  timber. 
They  are  now  considerably  grown  in  the  United  States. 

Sub-Tribe  III.  Pinece. — Scales  of  the  cone  spirally  arranged,  usually 
persistent.  Seeds  two  upon  each  scale.  Leaves  linear  (or,  in  some  cases, 
scale-like  on  the  primary  shoots),  spirally  arranged. 

Gen.  Tsuga,  Abies,  Picea,  Larix,  Pinus,  etc.  Tsuga  Canadensis,  the 
Hemlock-Spruce  of  the  Eastern  United  States,  and  T.  Douglasii  (Pseu- 
dotsuga  Douglasii  of  Carriere),  the  Douglas  Spruce  of  Oregon  and  Cal- 
ifornia, are  valuable  timber  trees.  The  former  attains  a  height  of  30 
metres  (100  ft.),  and  the  latter  of  nearly  100  metres  (300  ft.).  Both  are 
valuable  for  making  the  frames  of  houses  and  ehips. 


412  BOTANY. 

The  genus  Abies  contains  the  Balsam  Fir,  A.  bahamea,  of  Eastern 
United  States,  the  Silver  Fir  of  Europe,  A.  pectinatn,  the  Giant  Silver 
Fir,  A.  grandis,  of  Oregon  and  California,  besides  many  others.  All 
furnish  valuable  timber,  and  from  the  first  is  obtained  a  fine  turpentine 
known  as  Canada  Balsam. 

Picea,  excelsa,  the  Norway  Spruce  of  Northern  Europe,  is  a  large  tree 
30  to  50  met  res.  (100-1 50  ft.)  high,  from  which  white  deal  timber  is  ob- 
tained ;  from  its  turpentine  Burgundy  pitch  is  made.  P.  ulba,  the 
White  Spruce  of  Canada,  and  P.  Sitc/tensis  and  P.  pungens  of  the 
Western  United  States,  are  valuable  for  timber,  and  are  planted  for 
ornamental  purposes. 

Larix  Amemana,  the  Tamarack  or  American  Larch  of  Eastern 
North  America,  and  L.  Europcea,  the  Larch  of  the  mountains  of  Cen- 
tral Europe,  are  valuable  timber  trees  ;  from  the  latter  Venice  turpen- 
tine is  obtained. 

The  genus  Pinus  contains  many  important  trees  ;  they  may  be 
grouped  as  follows  : 

(a)  Leaves  in  fives. 

P.  Strobus,  the  White  Pine  of  Eastern  North  America ;  this  is  our 
most  valuable  species,  as  it  furnishes  the  greater  part  of  the  pine 
"lumber"  used  in  the  Northern  States  ;  it  often  attains  a  height  of 
50-60  metres  (160-200  ft.). 

P.  Lambertiana,  the  Sugar  Pine  of  California,  is  like  the  preceding, 
but  of  greater  size,  being  from  60  to  90  metres  high  (200-300  ft.). 

(b)  Leaves  in  threes. 

P.  auotralis,  the  Yellow  Pine  of  the  Southern  United  States,  fur- 
nishes a  durable  timber,  used  for  flooring,  shipbuilding,  etc.  Its  tur- 
pentine, which  is  obtained  by  cutting  into  the  trees,  yields  spirits  of 
turpentine  by  distillation  ;  the  residue  is  rosin.  Tar  is  obtained  by 
slowly  burning  the  wood  in  kilns  ;  and  by  evaporating  the  volatile 
matters  from  tar,  pitch  is  produced. 

P.  ponderosa,  the  Yellow  Pine  of  the  Rocky  Mountains  and  California, 
is  similar  to  the  former,  but  of  greater  size,  being  30-100  metres  high 
(100-300  ft.). 

(c)  Leaves  in  twos. 

P.  sylvestris,  the  "  Scotch  Fir,"  or  "  Scotch  Pine,"  is  a  native  of 
Northern  Europe  and  Asia.  Its  timber  is  extensively  used  in  England 
under  the  names  of  Dantzic  Fir  and  Riga  Fir,  in  the  building  of  ships, 
docks,  houses,  etc. 

P.  Larico  is  a  less  valuable  tree  of  Southern  Europe  ;  it  is  known  in 
this  country  as  Austrian  Pine,  and,  with  the  preceding,  is  commonly 
planted  with  us  for  ornamental  purposes. 

P.  resinosa,  the  Red  Pine  of  Canada,  is  a  tall  and  slender  tree,  much 
used  for  making  masts  and  spars. 

(d)  Leaves  single. 

P.  monophyttos,  the  Nut  Pine  of  the  Utah-Arizona  district,  is  pecu- 


GNETACE^S.  413 

liar  in  its  single  leaves.  Its  seeds  are  large  and  constitute  an  impor- 
tant article  of  food  for  the  Indians. 

Sub-Tribe  IV.  Araucarie.<p. — Scales  of  the  cone  spirally  arranged, 
deciduous.  Leaves  flat  or  four-angled,  often  broad,  sub-opposite,  or 
spirally  arranged. 

Gen.  Dammara,  Araucaria.  Dammara  australis  is  the  Kauri  Pine 
of  New  Zealand,  which  attains  a  heij-ht  of  60  metres  (200  ft),  and  is 
much  used  for  making  masts.  From  D.  alba  of  the  Malay  Islands 
Dammar  resin  is  obtained. 

The  genus  Araucaria  contains  large  pyramidal  trees  of  singular 
beauty.  A.  excelsa,  the  Norfolk  Island  Pine  of  the  South  Pacific  Ocean, 
is  45  to  60  metres  high  (150-200  ft.),with  horizontal  verticillate  branches, 
forming  a  pyramidal  head.  The  timber  is  valuable.  This  species 
and  A.  imbricata  from  Chili,  and  A.  Bidwttli,  of  Australia,  are  now 
grown  for  ornamental  purposes  in  California. 

Order  Gnetaceae. — The  Joint-firs  are  undershrubs,  or  small  trees, 
with  usually  jointed  rush-like  stems,  and  opposite  setaceous  or  oval 
leaves  (the  exceptional  Welwitschia  will  be  described  below).  The 
flowers  differ  from  those  of  the  other  Gymnosperms  in  always  having  a 
perianth — i.e.,  a  floral  envelope  ;  in  some  cases  this  is  single  and  bifid, 
while  in  others  it  is  composed  of  two  or  more  bract-like  bodies  (phyl- 
lomes).  The  stamens  are  single  (in  Gnetum),  or  six  to  eight  united 
into  a  tube  or  column.  The  ovules  are  single  in  each  flower,  and  are 
provided  with  one  or  two  envelopes  ;*  in  the  former  case  the  single 
integument,  and,  in  the  latter,  the  inner  one,  is  prolonged  beyond  the 
body  of  the  ovule  into  a  style-like  process,  which  is  occasionally  ex- 
panded above  into  a  stigma-like  body. 

The  flowers  are  disposed  in  the  axils  of  the  opposite  bracts  of  short 
lateral  branches  (aments  or  catkins),  which  spring  from  the  axils  of 
the  leaves  upon  the  main  stems. 

Three  genera  of  Gnetaceae  have  been  described,  viz.  :  (1)  Gnetum, 
with  from  fourteen  to  eighteen  species,  mostly  confined  to  the  East  In- 
dian islands  and  the  tropical  portions  of  South  America  ;  (2)  Ephedra, 
with  about  as  many  species,  widely  distributed  in  temperate  and  trop- 
ical regions  (five  species  occur  in  the  southwestern  part  of  the  United 
States) ;  (3)  Welwitschia,  with  but  one  South  African  species. 

*  In  Gnetum  Gnemon  there  are  three  envelopes  surrounding  the 
body  of  the  ovule,  but  it  is  probable  that  the  outer  one  is  to  be  re- 
garded as  belonging  to  the  perianth.  Some  botanists  reject  the  idea 
that  any  of  these  are  proper  ovule  integuments,  and  regard  the  inner 
one  as  "a  true  ovary,  and  the  outer  one  or  two  as  belonging  to  the  peri- 
anth or  staminal  whorl.  This  is  the  position  taken  by  Parlatore  in 
De  Candolle's  "  Prodromus  ;"  by  Beccari,  in  "  Nuovo  Giornale  Botan- 
ico  Italiano,"  Jan.,  1877  (Delia  Organogenia,  etc.,  del  Gnetum  Gnemoit); 
and  by  Dr.  Gray,  in  "  Bot.  Text-Book,"  6th  ed.,  1879,  vol.  1,  p.  269. 


414 


BOTANY. 


ONSTAGE^!.  415 

The  most  remarkable  member  of  the  order  is  Welwitschia  mimbilis 
(Fig.  302)  discovered  by  Dr.  Welwitsch  in  1860,  and  described  by  Dr. 
Hooker  in  1862.*  It  consists  of  a  short,  thick,  woody  stem  rising 
30  cm.  (1  ft.)  above  the  ground,  and  having  a  diameter  of  from  30  to 
50  cm.  (12  to  20  in.),  and  even  attaining  in  some  cases,  according  to  the 
discoverer,  a  diameter  of  1.4  metres  (4f  It.).  From  the  lower  portion 
of  this  stem  a  stout  tap-root  passes  downward,  branching  more  or  less 
at  its  lower  end.  The  top  of  the  stem  is  nearly  flat,  there  being  usu- 
ally a  slight  depression  across  its  diameter.  There  are  only  two  leaves 
attached  to  this  curious  stem,  and  from  the  study  of  the  young  plants 
it  seems  probable  that  they  are  the  persistent  cotyledons.  They  arise 
in  two  deep  grooves  in  the  circumference  of  the  upper  part  of  the  stem, 
and  as  they  continue  to  grow  at  their  bases  they  eventually  attain  a 
great  length,  being  nearly  two  metres  long  (6  ft.)  in  full  grown  plants. 
They  are  thick  and  leathery  in  texture,  and  their  fibro-vascular  bun- 
dles are  all  parallel  and  free  from  each  other,  running  from  the  base  of 
the  leaf  to  its  split  and  frayed  apex.  From  the  circumference  of  the 
stem,  above  and  close  to  the  bases  of  the  leaves,  spring  stout  branching 
peduncles,  which  bear  clusters  of  scarlet  cones  (Figs.  302  and  303). 
These  cones  are  composed  of  numerous  opposite  bracts  arranged  in 
four  rows.  In  the  axil  of  each  bract  there  is  a  single  flower,  consist- 
ing in  the  male  cones  of  a  perianth  of  two  pairs  of  decussating  bracts 
enclosing  a  ring  of  partly  united  stamens  ;  within  these  is  a  rudimen- 
tary, abortive  ovule,  whose  single  coat  is  curiously  prolonged  so  as  to 
resemble  a  pistil  with  style  and  expanded  stigma.  In  the  flowers  of 
the  female  cones  the  perianth  is  a  compressed,  winged  tube,  lying 
within  the  broad  scales.  There  are  no  rudiments  of  stamens ;  and  in 
the  centre  of  the  perianth  there  is  placed  a  single  erect  ovule  with  one 
elongated  integument. 

It  will  thus  be  seen  that  the  cones  of  WelwitscJiia,  while  bearing 
some  external  resemblance  to  those  of  Conifers,  are  not  homologous 
with  them  ;  in  Welwitschia  they  are  short,  flower-bearing,  bracted  axes  ; 
in  Coniferse  they  are  stamen-bearing  or  pistil-bearing  axes,  in  other 
words,  each  cone  is  a  multistaminate  or  multiovulate  flower. 

Fossil  Gymnosperms. — Gymnosperms  first  appeared  in  the  Devo- 
nian, in  which  they  were  represented  by  species  of  Prototaxis,  Cladoxy- 
lon  and  Schizoxylon,  doubtfully  referred  by  Schimperf  to  the  Couiferae. 
True  conifers  were  present  in  the  Carboniferous,  in  the  Permian  they 
were  abundant,  and  in  the  Tertiary  exceedingly  so.  Araucaria  was 
represented  in  the  Jurassic  by  several  species.  Pinus,  Abies,  Cedrus 
and  Sequoia  originated  during  the  Cretaceous  period,  and  were  repre- 

*  "  On  Welwitschia,  a  new  Genus  of  Gnetaceae,"  by  J.  D.  Hooker, 
in  "Transactions  of  the  Linnean  Society,"  Vol.  XXIV. 

f  "  Traite  de  Paleontologie  Vegetale""  par  W.  Ph.  Schimper,  Paris, 
1869-1874. 


416  BOTANY. 

sented  by  many  species  during  the  Tertiary.  It  is  interesting  to  note 
that  the  present  small  and  restricted  genus  Sequoia  was  during  Cre- 
taceous and  Tertiary  times  large  and  widely  distributed  throughout  the 
northern  hemisphere.  In  this  country  two  Cretaceous  species  are  re- 
corded from  Nebraska  and  Kansas,  and  eight  species  from  the  Tertiary 
of  Colorado,  Utah,  Montana,  and  the  region  westward. 

The  Cycads  originated  in  the  Carboniferous,  and  increased  in  num- 
bers to  the  Jurassic,  in  which  twenty  or  more  genera  were  richly  repre- 
sented in  species.  A  Cretaceous  species  of  PteropJtyllum  from  Nebraska, 
and  a  tertiary  Zamio»trobus  from  Colorado  have  been  described. 

Two  species  of  Ephedra  from  the  Tertiary  of  Europe  are  the  only 
known  fossil  Guetacese. 

§  III.    CLASS  ANGIOSPERM^E. 

522. — This  class  includes  the  great  mass  of  the  so-called 
flowering  plants.  The  principal  characters  which  set  these 
off  from  the  preceding  small  class  of  the  Phanerogams 
(Gymnospermse),  are  (1)  the  development  of  an  ovary,  and 
(2)  the  aggregation  of  the  reproductive  organs  into  a  defi- 
nite and  distinct  flower. 

523. — The  plants  of  this  class  have,  in  most  cases,  more 
or  less  elongated  stems  ;  these  are  solid  at  first,  and  in  the 
great  majority  of  cases  they  remain  so.  They  usually  bear 
ample  leaves  with  a  parallel  (in  the  Monocotyledons),  or 
netted  venation  (in  the  Dicotyledons).  The  disposition  of 
the  fibro-vascular  bundles  in  the  stem  is  either  like  that  in 
the  Gymnosperms  (in  most  Dicotyledons),  or  they  run 
through  the  fundamental  tissues  parallel  to,  but  independent 
of,  one  another  (in  most  Monocotyledons).  In  the  former 
case,  the  stems  of  the  perennial  species  increase  in  diameter, 
in  the  same  way  that  they  do  in  Gymnosperms,  and  there  is 
here  also  a  well-marked  division  into  pith,  wood  and  bark  ; 
in  the  latter  case  there  is  usually  no  increase  in  the  diameter 
of  the  stem  after  it  has  elongated,  and  in  tne  few  cases  of 
considerable  increase  it  takes  place  by  methods  very  different 
from  that  described  in  the  preceding  class. 

Most  Angiosperms  are  terrestrial  and  chlorophyll-bearing 
plants  ;  there  are,  however,  many  aquatic  and  aerial  species, 
and  a  considerable  number  of  parasites.  They  range,  also, 
in  size  and  duration,  from  minute  annuals,  a  millimetre  in 


ANGIOSPERM.fi. 


417 


extent,  to  enormous  trees,  50  to  100  metres  high,  and  often 
several  or  many  centuries  old. 

524.  —The  flowers  of  the  Angiosperms,  while  sometimes 
so  reduced  as  to  be  quite  simple,  are  in  all  cases  much  more 
complex  than  those  of  Gymnosperms.  In  most  cases  they 
are  monoclinous  (hermaphrodite),  i.e.,  the  male  and  female 
sexual  organs  occur  in  the  same  flower ;  in  such  case  each 
flower  consists  essentially  of  an  axis  bearing  one  or  more 
pollen  -  producing  organs 
(anthers,  Fig.  304,  a),  and 
one  or  more  ovule-contain- 
ing organs  (ovaries,  Fig. 
304,  F).  These  are,  when 
more  than  one,  generally 
arranged  upon  the  axis  in 
one  or  more  Avhorls  ;  the 
staminal  whorls  normally 
arise  below  the  ovaries.  Be- 
sides these  essential  organs, 
there  are  usually  secondary 
or  accessory  organs,  such  as 
the  delicate,  and  frequent- 
ly Colored  floral  leaves  (  pet-  Fig.  ,m -Diagrammatic  section  of  an  an- 

als  or  sepals,  JT  and  Ke,  $®?SZ^&  a%^&%^ 
Fig.  304),  the  honey  glands,  S8^p^/r™  ^heovlry  fXe' 

pj-p  style,  and  n  the  stigma  of  the  pistil— the 

ovary  contains  one  ovule,  which  has  a  single 

525  — The  axis  Of  the  coa*'  *•  enclosing  the  ovule  body,  S;  em,  the 
embryo  sac  ;  JS,  germ  cell  or  germinal  vesi- 

flower  (the  TorUS  or  Re-  cle •.:  pi,  a  pollen-tube  penetrating  the ,  style, 
and  reaching  the  germ-cell  through  the  mi- 

ceptade),     usually    remains    cropyle  of  the  ovule.-After  PraisS. 

very  short,  so  that  the  different  organs  of  the  flower  are 
closely  approximated,  and  thus  distinctly  set  off  from  the 
other  parts  of  the  plant.  The  axis  is,  moreover,  but  very 
rarely  prolonged  beyond  the  flower,  all  growth  ceasing  in  it 
when  the  floral  organs  are  developed.  In  most  cases  the  re- 
ceptacle is  conical  or  hemispherical  in  shape  ;  in  other  cases 
it  develops  into  various  shapes,  the  principal  ones  of  which 
will  be  noticed  hereafter. 

526. — The  lower  portion  of  the  flower  axis  generally  bears 
one  or  moiv  whorls  of  modified  leaves  (phyllomes),  which 


418  BOTANY. 

constitute  the  floral  envelopes,  or,  technically,  the  perianth. 
Frequently  there  is  a  strong  difference  between  the  outer  and 
inner  whorls,  and  in  such  cases  the  former  is  distinguished 
as  the  calyx,  and  the  latter  as  the  corolla. 

527. — The  whorl  of  stamens  (technically  the  Andrcecium) 
develops  above  the  upper  whorl  of  the  perianth.  Each 
stamen  generally  consists  of  a  slender,  thread-like  stalk  (fila- 
ment), bearing  upon  its  upper  extremity  from  one  to  four 
pollen-sacs ;  this  pollen-containing  portion,  whether  one  or 
more  celled,  is  known  as  the  anther.  In  its  development 
the  stamen  at  first  bears  a  close  resemblance  to  a  rudimentary 
leaf,  both  in  structure  and  position,  and  there  can  be  no 
doubt  that  it  is  a  phyllome,  modified  into  a  pollen-produc- 
ing organ.  Whether  the  anther  is  to  be  regarded  as  an  out- 
growth of  the  phyllome,  or  as  its  modified  upper  portion,  is 
doubtful ;  analogy  would  indicate  the  probability  of  the 
former  view.  There  can  be  bat  little  doubt  that  the  pollen- 
sacs  are  to  be  considered  homologous  with  the  microspo- 
rangia  of  the  higher  Pteridophytes,  and  the  latter  are  clearly 
outgrowths  (trichomes  ?)  upon  phyllomes. 

528. — The  pollen- grains  are  developed  here  as  in  Gymno- 
sperms,  from  pollen  mother-cells  ;  the  latter  are  differentiated 
parenchyma  cells,  lying  in  or  near  the  axis  of  the  pollen- 
sacs.  Each  mother-cell  undergoes  two  divisions  (by  fission), 
producing  four  parts,  which  become  as  many  pollen-grains. 
The  mature  pollen-grain  is  a  single  cell,  and  consists  of  a 
mass  of  protoplasm  mixed  with  oil-drops,  starch  granules, 
etc.,  surrounded  by  two  investing  membranes,  an  outer  hard 
and  firm  one  (the  extine),  and  an  inner  thin  and  delicate  one 
(the  inline).  In  the  germination  of  the  pollen-grains,  they 
always  remain  single  cells,  there  being  no  formation  of  in- 
ternal cells  (rudimentary  prothallium)  as  in  the  Gymuo- 
sperms.  The  development  of  the  pollen-tube  takes  place  as 
in  Gymnosperms,  by  a  prolongation  and  growth  of  the 
intine,  but  here  the  extine  is  not  slipped  off  in  the  process, 
but  only  pierced  in  certain  thin  areas  of  its  surface.  Usually 
but  one  tube  issues  from  each  pollen-grain,  but  in  some 
cases — e.g.,  (Enothera — two  or  more  are  sometimes  found. 

529. — The  female  reproductive  organs  (individually  the 


ANGlOSPERMjfi.  419 

pistils,  and  collectively  the  Gytmcium)  normally  develop 
upon  the  uppermost  portion  of  the  flower-axis,  and  within 
the  whorl  of  stamens.  They  consist  of  one  or  more  infolded, 
ovuliferous  phyllomes  (carpophylla)  whose  margins  are 
united  so  as  to  form  separate,  or  more  or  less  united  cavi- 
ties (ovaries).  The  apical  portions  of  the  carpophylla  are 
usually  extended,  terminating  in  a  mass  of  loose  parenchy- 
matous  tissue,  the  stigma.  The  ovules  arise  as  outgrowths 
(trichomes,  in  the  broader  sense  of  the  term)  upon  some 
portion  of  the  interior  surface  of  the  ovary ;  they  most  fre- 
quently develop  upon  the  margins  of  the  carpophylla, 
although  they  are  by  no  means  confined  to  them.  In  some 
cases  there  is  but  a  single  ovule  in 
each  ovary,  in  others  they  range 
from  a  few  to  several  hundred.  In 


many  cases,  especially  when   the         ^w* 
ovules  are  numerous,  the  ovulifer- 
ous portion  of  the  ovary  is  devel-  -A  B 

oped  into  a  thickened  mass  of  tis-      Fig.  305.—  very  young  ovules  of 
sues,  the  placenta,  which  projects 
more  or  less  into  the  ovary  cavity. 
530,-Each   ovule  is  at  first  a 

homogeneous  maSS  of  parenchyma-    aec 
,*  %  velo 


nclinc)  is  just  beginning  to  de 


,  elop  as  a  ring,  se  ;  in  B  there  are 

toilS  tiSSUe,    Constituting    the    body  two  rings,  the  upper  being  the  ru- 

/                  ii    j           i        \     <  iu              i  climentary  secundine,  the    lower 

(Or  SO-Called  nucleus)  Of  the  OVUle  ;  the  prlmine.      X  140.—  After  Du- 

a  little  later  a  circular  ridge  arises  chartre- 
upon  the  ovule  body  ;  this  grows  upward,  and  forms  an  in- 
tegument ;  a  second  integument  generally  forms  in  exactly 
the  same  way  outside  of  the  first  (Fig.  305,  A  and  B}.  From 
their  position  when  fully  formed,  these  coats  have  received 
the  names  primine  and  secundine,  the  former  being  applied 
to  the  outer,  the  latter  to  the  inner.*  The  coats  never  com- 
pletely enclose  the  body  of  the  ovule,  there  always  remaining 
a  small  opening  (the  micropyle)  over  its  apex  (m,  Fig.  306, 

*  These  terms  were  so  applied  by  Mirbel,  who  was  not  acquainted 
with  the  order  of  development  of  the  coats.  Schleiden  applied  them 
in  exactly  the  opposite  way,  which  has  led  to  some  confusion.  Mir- 
bel's  use  of  the  terms,  although  not  as  good  as  Schleiden's,  is  the  pre- 
vailing one. 


420 


BOTANY. 


A).  In  their  development  most  ovules,  although  straight 
(Fig.  306,  A]  at  first,  become  afterward  more  or  less  curved 
upon  themselves  (Fig.  306,  B  and  C}. 

The  development  of  the  embryo  sac  takes  place  in  a  much 
simpler  way  in  Angiosperms  than  in  Gymnosperms.*  An 
axial  cell  enlarges  greatly,  becoming  thus  the  young  embryo- 
sac  (Fig.  306,  em).  In  preparation  for  fertilization,  it  divides 
into  a  row  of  several  (3-6)  cells,  the  uppermost  of  which 
forms  four  nuclei,  one  of  which  becomes  the  germ-cell. 
By  the  absorption  of  the  cell  wall,  the  upper  cell  fuses 
with  the  second  (which  may  or  may  not  contain  four  nuclei), 
forming  a  common  cavity  containing  many  nuclei  or  young 


Fig.  806. — Diagrammatic  longitudinal  sections  of  ovules.  A,  the  straight  ovule  (or- 
thotropous) ;  k,  the  body  of  the  ovule,  with  its  embryo  sac,  em  ;  at,  the  outer  ovule 
coat  (primine) ;  it,  the  iniier  coat  (*<  cundine) ;  m,  the  micropyle  ;  c,  the  base  of  the 
ovule,  where  th«  coats  arise,  called  also  the  cliala/.a;  /,  the  ovule  stalk  or  I'uniciilus. 
.B.an  inverted  ovule  (anatropous) ;  the  long  funicnlus,/,  has  fused  with  the  primine  of 
one  side  of  the  ovule  and  formed  the  raphe,  r.  C,  a  bent  ovule  (campylotropous).— 
After  Prantl. 

cells,  several  of  which,  including  the  Germ-Cell,  remain  at 
the  top,  the  others  (Antipodal  Cells)  occupying  the  lower 
part.  No  endosperm  is  to  be  seen  at  this  stage,  f 

The  fertilization  of  the  germ-cell  involves  two  operations, 
viz.,  Pollination — i.e.,  the  deposition  of  the  pollen  upon  the 
stigma,  and  Fertilization  proper. 

*  See  "  Nouvelles  Recherches  sur  le  developpement  du  sac  embryon- 
naire  des  Phanerogames  angiospermes,"  by  Julien  Vesque,  in  Annales 
des  Sciences  Naturettes,  1879. 

t  The  endosperm,  which  here  forms  after  fertilization  of  the  germ- 
oell,  may  be  regarded  as  a  belated  piothallium.  It  is  here  no  longer 
necessary  for  the  prothallium  to  precede  the  formation  of  the  germ- 
cell  ;  there  is  consequently  a  considerable  retardation  in  its  develop- 
ment. 


ANGIOSPERM^E.  421 

531.  Pollination.— As  the  pollen-grains  are  entirely  want- 
ing in  means  of  locomotion,  they  are  dependent  for  trans- 
portation to  the  stigma,  upon  (1)  the  wind  (anemophilous 
flowers)  ;  (2)  certain  contrivances,  by  means  of  which  insects 
(or  rarely  birds)  are  made  to  carry  the  pollen  from  anther  to 
stigma  (entomophilous  flowers)  ;  (3)  the  favorable  position  of 
the  anthers  and  stigmas,  bringing  the  pollen  in  the  open- 
ing anther  into  contact  with  the  stigmatic  surface  (auto- 
gamous flowers).  The  grasses  and  sedges,  and  the  oaks, 
beeches,  chestnuts,  walnuts,  birches,  and  their  allies,  and  a 
few  others,  have  anemophilous  flowers.  In  these  the  pollen 
is  produced  in  great  abundance,  and  the  flowers  are  small, 
uncolored,  and  destitute  of  nectar  (honey).  An  immense 
number  of  plants  have  entomophilous  flowers  ;  these  are,  as 
a  rule,  large,  colored,  and  provided  with  nectar-secreting 
glands;  the  nectar  acts  as  a  bait,  and  the  showiness  as  a 
guide  to  honey-loving  insects,  which,  by  various  structural 
contrivances  in  the  flowers,  are  made  to  come  successively 
in  contact  with  the  anthers  of  one  flower  and  the  stigmas  of 
the  next,  in  the  first  dusting  their  bodies  with  pollen,  which 
in  the  second  adheres  to  the  stigmas.  Autogamous  flowers 
are  much  less  numerous  than  either  of  the  foregoing,  and  it  is 
doubtful  Avhether  there  are  any  species  of  plants  all  of  whose 
flowers  exhibit  constant  autogamy.  There  are  a  good  many 
plants,  however,  which  have  two  forms  of  flowers,  viz.,  large, 
showy,  nectar-bearing,  entomophilous  ones,  and  small,  in- 
conspicuous autogamous  ones,  generally  with  a  rudimentary 
perianth.  Flowers  exhibiting  this  form  of  autogamy  are 
said  to  be  cleistogamous.  Examples  are  to  be  met  with  in 
Viola,  Lithospermum,  Impatiens,  etc.  ;  early  in  the  season 
these  have  large  flowers,  which  are  entomophilous,  but  later 
only  small  cleistogamous  ones  appear,  and  in  some  species  of 
Viola  these  are  subterranean.  Without  doubt  it  frequently 
happens  that  the  pollen  of  anemophilous  and  entomophilous 
flowers-  falls  upon  their  stigmas,  resulting  in  accidental  auto- 
gamy, but  too  frequent  a  recurrence  of  this  is  guarded  against 
by  various  structural  devices.* 

*  Upon  tliis  interesting  subject  the  student  is  referred  to  Mr.  Dar- 
win's works,  "  The  Various  Contrivances  by  which  Orchids  are  Fertil- 


422 


BOTANY. 


532.  Fertilization. — Fertilization  takes  place  as  follows  : 
The  pollen  grain,  resting  upon  the  moist  surface  of  the 
stigma,  absorbs  moisture  and  germinates,  sending  out  a  tube 
which  penetrates  the  soft  tissues  of  the  stigma  and  style. 
finally  reaching  the  cavity  of  the  ovary,  where  it  enters  the 
micropyle  of  an  ovule  (Fig.  307,  A}.  Here  it  comes  in  con- 
tact with  the  apex  of  the  ovule  body,  through  whose  tissues 
it  forces  its  way  until  it  reaches  the  embryo  sac  ;  in  some 

cases,  however,  the 
embryo  sac  has  grown 
out  through  the  apex 
of  the  ovule  body 
into,  and  occasionally 
through  the  micro- 
pyle, thus  meeting  the 
pollen  -  tube.  T  h  e 
transfer  of  the  con- 
tents of  the  pollen- 
tube  to  the  germ-cell 
has  never  been  ob- 
served, but  doubtless 
it  takes  place  by  diffu- 
sion through  the  pol- 


leu-tube and  embryo 

the  placenta  ;  «?,  the  raphe,  swollen  at  this  point  fa,    cop        Tlip   fir<sf   VP«II li- 
the outer  coat  of  the  ovule  ;  i,  the  inner  ;»,  the  pol-    SaC'       •Liie  llrst   1( 

licropyfe ;  e,  .em-  of  fertilization  is  the 


Pig.  307. — A,  a  longitudinal  nctionof  the  anatro- 
pous  ovule  of  Viola  tricolor,  after  fertilization,    pi, 

raphe,  swollen  at  this  point ;  a, 

ovule  ;  i,  the  in 

Jen-tube  which  has  entered  the  mi 
bryo  sac,  with  the  very  young  embryo  at  the  micro- 
pylar  end,  and  numerous  free  endosperm  cells  at  the    formation  of  a  Wall  01 
other.    S,  apex  of  embryo  sac.  e  (much  more  mag         „    , 

nified) ;  eb,  very  young  embryo  of  two  cells, support-    C6liUl086     ai'OUnu    the 
ed  by  a  two-celled  suspensor.     C,  the  same,  further  ,,         . ,        ,    , 

advanced.    All  the  figures  highly  magnified.-After    germ-cell  ;     the   latter 

soon  divides  trans- 
versely one  or  more  times,  and  thus  gives  rise  to  a  row  of 
cells,  the  suspensor,  at  the  free  extremity  of  which  a  rudi- 
mentary embryo  is  soon  formed  by  the  fission  of  cells  in 
three  planes  (Fig.  307).  Simultaneously  with  the  foregoing 


ized  by  Insects  ;  "  "  The  Effects  of  Cross  and  Self-Fertilization  in  the 
Vegetable  Kingdom  ; "  "  The  Different  Forms  of  Flowers  on  Plants  of 
the  Same  Species."  Also  Lubbock's  "  British  Wild  Flowers  Considered 
in  Relation  to  Insects,"  and  Dr.  Gray's  "  How  Plants  Behave." 


ANGIOSPE111LE. 


423 


development  in  the  apical  portion  of  the  embryo  sac,  there  is 
a  corresponding  one  in  the  basal  portion.  The  protoplasm 
gathers  about  certain  points,  and  gradually  condenses  so  as 
to  form  as  many  free  and  naked  cells  (Fig.  308).  These 
soon  become  covered  with  cell-walls,  and  they  then  multiply 
rapidly  by  fission,  until  they 
fill  up  the  embryo  sac  with  a 
continuous  tissue,  the  endo- 
sperm. (Consult  p.  41,  and 
Fig.  33,  A  and  B.) 

533.  The  Development  of 
the  Embryo.    (Figs.  309  and 

31  O\         A  a  eHfpil   -ibm-0    mir>  of    «perm-cells  which  have 

Jiuj. — AS  stated  auovc,  one  oi  protop|a!im.  J)r_  Highly  magnifled.- 
the  first  results  of  the  fertili-  After  Sachs- 
zation  of  the  germ-cell  is  the  formation  of  a  row  of  from 
two  to  many  cells,  the  suspensor  or  pro-embryo,  the  first  or 
proximal  cell  of  which  is  attached  to  the  wall  of  the 
embryo  sac  close  to  the  micropyle  of  the  ovule  ;  its  distal,  or 
free  end,  always  grows  toward  the  interior  of  the  ovule,  and 


Fig.  308.— Posterior  part  of   the  em- 
bryo sac  of  Viola  tricolor,  e,  its  wall  ;  x, 
cavity  of  the  sac ;  A'  Jf,  young  endo. 
formed   in  the 


Fig.  309.— Embryos  of  Allinm  c,?p>i.  /.,  very  yonntr  stage  ;  c,  b,  cells  of  suspcnsor  : 
a,  the  single  roll  constituting  the  embryo  ;  x,  sin  unfertilized  germ  cell  //..  an  older 
stage,  the  embryo  now  two-celled  ,  eg,  the  wall  of  the  embryo  sac.  ///.,  a  still  later 
stage.  Much  magnified.— After  Sachs. 

its  last  cell  becomes  transformed  bv  successive  fissions  into  a 
several-celled  surface  (/.,Fig.  310)  ;  by  a  continuation  of  the 
process  a  many-celled  solid  body  is  formed  (//.,  Fig.  310)  ; 
partitions  then  arise  in  the  cells  parallel  to  the  surface,  and 
the  external  layer  of  daughter-cells  thus  formed  constitutes 
the  dermatogen  or  primary  epidermis  (///.,  Fig.  310). 


424 


BOTANY. 


About  this  time  there  is  inmost  cases  a  slight  differentiation 

of  the  inner  cells, 

/r/§£&£g:?\  /?^f^\  /  '  foreshadowing  the 

future  tissue  sys- 
tems (///.  a  n  d 
IV.,  Fig.  310).  A 
little  later  the  cot- 
yledons (one  or 
two)  appear ;  in 
the  Monocotyle- 
dons, in  one  side  of 
the  thallus  -  like 
structure  a  depres- 
sion forms,  which 
becomes  the  punc- 
tum  vegetationis  of 
the  embryo,  and 
marks  the  limits  of 
the  stem  and  single 
cotyledon  ;  in  the 
Decotyledons  two 
cotyledons  grow 
out  symmetrically 
from  the  disuil  end 
of  the  thallns-like 
structure,  and  the 
depression  between 

Fig.  310,-Developmcnt  of  the  embryo  of  Capsella  them  becomes  the 
Bwrxii-pastorii  (highly  magnified).  /..  »>.  snspensor,  or 
pro-embryo  of  five  cells,  and  terminated  by  a  four-celled 
embryo;  1-1,  the  longitudinal  wall  which  divided  the 
first  embryo-cell  into  two  cells;  2-2.  transverse  wall 
which  divided  each  cell  of  the  two-celled  embryo,  mak- 
ing it  four  celled.  //.,  v.  snspensor;  h,  the  hypophysis, 


fionis     (V.,     Fig. 
310).     The  root  is 


the  basal  part  of  tl.e  embryo"  formed  by  th.-  ilivi.ion  of    the   last   portion  of 

1  of  the  snspensor  ;  the  shaded  portion  of  the 
nbryo  is  the  dcrmatog.-n  or  primary  epidermis     ///.,     the    CinbryO     fomi- 


il> 


embryo  further  advanced;  the  iui»»  .-,,.......  ^c..=  »,«..-  ,                       .  . 

etitute  the  plerome,  between  these  and  the  dermatogen  CU  I  its  Cap  (the  l)ll- 

to  the  right  and  left  are  the  cells  of  the  periblem  ;  the  ,  .      v  •     j         i 

hypophysis  is  divided  into  two  cells,  ft,  h'.    IV.,  still  CorhlZa)  IS  develop- 

older  condition.     V.,  embryo  considerably  advanced  ;  -j     »                  i                • 

c,  c.  cotyledons  ;  «.  apex  of  stem  ;  the  dermatogen,  perl-  Cd    tl'Om    a  layer  OI 

Mem,  and  pb-rome  shown  as  before;  w,  the  rudiment-  n.vn0  V00nlrino-  frnm 

ary  root,  and  root-cap   formed   from  the  cell  h' of  HI.  CCllS  ICSUltlllg  IlOm 

and  /K-After  Hiiwtein.  tl)C    succeg8ive    fis- 

sion  of  the  penultimate  cell  of  the  snspensor,  the  hypophy- 


ANQIOSPERM^.  425 

sis  (h,  Fig.  310,  //.,  ///.,  IV.,  F.).  The  growing  points  of 
both  root  and  stem  develop  in  all  cases  from  masses  of 
small  cells,  and  never  from  single  apical  cells. 

The  development  of  the  embryo  may  be  studied  by  selecting  the 
young  ovaries  of  Capsella  Bursct-pastoris,  or  Lepidium  intermedium,  and 
dissecting  out  the  ovulei  in  a  solution  of  potassic  hydrate,  and  after- 
wards transferring  them  to  a  solution  of  glycerine  and  water.  Speci- 
mens prepared  in  this  way  show  clearly  the  embryo  sac  with  the  con- 
tained suspensor  and  embryo  when  examined  by  means  of  a  magnify- 
ing power  of  from  one  hundred  and  fifty  to  four  hundred  diameters. 
When  they  have  been  made  too  transparent  by  this  treatment,  their 
walls  may  be  rendered  more  opaque  by  the  addition  of  a  dilute  solution 
of  alum.  The  young  embryo  may  sometimes  be  separated  from  the 
ovule  by  a  gentle  pressure  upon  the  top  of  the  cover-glass. 

534.  The  Endosperm. — During  the  early  part  of  the  de- 
velopment of  the  embryo,  just  described,  the  formation  of 
endosperm  cells  Avithin  the  embryo  sac  takes  place  with  great 
rapidity  ;  in  most  cases  the  growth  of  the  endosperm  is  so 
great  as  to  displace  the  greater  part  or  even  the  whole  of  the 
surrounding  tissues.     The  cells  of  the  endosperm  contain 
large  quantities  of  nutrient  matters,  which  are  at  first  in  so- 
lution, but  Avhich  later  may  pass  into  a  less  soluble  condition. 
The  growing  embryo  is  imbedded  in  the  endosperm,  and  as 
the  former  increases  in  size,  the  latter  is  displaced  and  ab- 
sorbed.    In  many  cases  the  growth  of  the  embryo  is  arrested 
before  the  endosperm  is  all  absorbed — e.g.,  in  Ranunculaceas, 
Violaceae,  Solanacese,  Euphorbiaceae,    Palmacese,   Liliaceae, 
Gramineae,  etc.  ;  in  other  cases  the  embryo  continues  to  grow 
until  it  has  entirely  absorbed  the  endosperm — e.g.,  Crucifera?, 
Rosaceae,    Myrtaceae,    Compositae,    Salicaceae,    Cupuliferae, 
Alisrnaceae,  etc. 

535.  The  Perisperm. — It   rarely  occurs  that   the  endo- 
sperm develops  but  slightly,  and  in  such  cases  there  is  a  con- 
siderable development  of  the  tissues  of  the  ovule  surround- 
ing the  embryo  sac,  constituting  the  perisperm  ;  in  such 
cases  nutrient  matters  are  contained  in  the  latter,  which 
functionally  replaces  the   endosperm.      Examples  of   this 
structure  occur  in  Nymphaeaceas,  Piperaceae,  and  Cannaceae. 

536. — During  the  growth  of  the  embryo  the  ovule  and 
ovary  undergo  considerable  changes.  The  outer  coat  of  the 


426  BOTANY. 

ovule  becomes  hardened  by  the  conversion  of  parenchyma 
into  sclerenchyma,  thus  forming  the  testa  ;  in  other  cases  it 
becomes  more  or  less  pulpy,  as  in  Magnolia,  Pceonia,  etc. 
The  outer  coat  is  liable  to  be  much  modified  in  form  also, 
being  sometimes  developed  into  thin  wings,  or  a  tuft  or 
covering  of  hairs,  as  in  Bignonia,  Asdepias,  Gossypium,  etc. 
The  inner  coat  usually  undergoes  little  change,  generally  be- 
coming thin  and  dry.  The  ovary  in  many  cases  becomes 
hard  and  dry — e.g.,  in  Cupuliferae  and  Leguminosae ;  in 
others  it  is  more  or  less  pulpy,  as  in  the  Cherry,  Plum, 
Blackberry,  etc.  Both  ovule  and  ovary  at  maturity  (now 
called  seed  and  pericarp  respectively,  and  the  latter,  with  all 
its  contained  seeds,  the  fruit]  spontaneously  separate  from 
their  supporting  parts,  by  the  breaking  away  of  the  walls  of 
certain  layers  of  cells. 

The  development  of  the  flower  as  a  whole,  or,  as  it  is  termed,  the  Or- 
ganogeny  of  the  flower,  is  an  important  and  instructive  subject  of 
study.  The  law  of  greater  structural  similarity  in  the  earlier  stages  of 
organisms  becomes  very  evident  when  we  look  carefully  into  the  de- 
velopment of  flowers.  Very  many  flowers  which,  when  fully  formed, 
have  little  resemblance  to  each  other,  are  found  to  be  exactly  alike  in 
their  earlier  stages.  Relationships  are  thus  indicated  where  they 
would  otherwise  hardly  be  detected. 

Without  entering  further  upon  this  subject,  which  would  require 
several  volumes  for  its  fu.ll  treatment,  it  need  only  be  said  here  that 
all  the  floral  organs  are  essentially  alike  in  form  and  structure  upon 
their  first  appearance ;  the  sepals,  petals,  stamens,  and  pistils  appear 
at  first  as  small  papillae,  and  it  is  only  after  they  have  grown  somewhat 
that  the  nature  of  the  nascent  organ  can  be  determined  by  its  sliape. 
Moreover,  it  is  found  (as  has  so  often  been  seen  in  the  development  of 
animals)  that  the  rudiments  of  some  organs  which  are  wanting  in  the 
fully-formed  flower  are  present  in  its  earlier  stages,  a  fact  of  no  less 
significance  in  the  comparative  anatomy  of  plants  than  of  animals. 

The  general  appearance  of  the  parts  of  the  very  young  flower,  and 
their  development,  are  well  shown  in  the  accompanying  figures  from 
Hofmeister  (Figs.  311-313).* 

Glossology  of  Angiosperms. — The  great  number  of  species  of  An- 
giosperms  and  the  multitude  of  forms  assumed  by  different  parts  of 

*  The  student  who  wishes  to  study  this  subject  further  may  profit- 
ably consult  Hofmeister's  "  Allgemeine  Morphologic  der  Qewachse," 
Leipsig,  1868,  and  Payer's  "  Organogenic  de  la  Fleur,"  Paris,  1857. 


GLOSSOLOGY  OF  AfiQIOSPERMS. 


427 


the  plant,  have  made  necessary  the  use  of  many  descriptive  terms,  the 
principal  ones  only  of  which  will  be  noticed  here. 

Inflorescence. — The  arrangement  of  the  flowers,  whether  singly,  or 
in  groups  upon  a  more  or  less  branched  axis,  is  termed  inflorescence. 
The  branching  of  the  axis  in  flower  groups  is  almost  universally  mono- 


FIG  313. 

Figs.  311-13.— Three  successive  stages  in  the  development  of  the  flower  of  the  Rose 
(Roaa  canina).  In  all  the  figures,  e,  c  are  the  sepals  ;  p,  p,  petals  ;  st,  stamens ;  cp, 
carpels  or  pistils.  Magnified.— After  Hofmeister. 

podial,  a  few  cases  only  (and  they  doubtful  ones)  have  been  regarded  as 
dichotomous. 

Monopodial  flower  clusters  fall  under  the  two  types Botryose  and  Cy- 
mose,  referred  to  in  paragraph  177  (page  139).  In  Botryose  inflores- 


428  BOTANY. 

cence  the  flowers  are  properly  lateral  upon  the  main  axis,  or  the  sec- 
ondary axes.  The  flowers  develop  in  acropetal  (centripetal)  order,  and 
when  the  axis  continues  to  grow  the  cluster  may  become  indefinitely 
extended,  whence  it  is  called  indeterminate.  In  Cymose  inflorescence 
every  flower  is  properly  terminal  upon  a  main  axis  or  one  of  the  sec- 
ondary ones.  In  every  flower  cluster  the  main  axis  is  first  terminated 
by  a  flower  ;  lateral  branches  (secondary  axes)  then  arise  at  some  dis- 
tance below  the  apex,  and  each  of  these  is  terminated  by  a  flower  ; 
lateral  branches  terminated  by  flowers  arise  on  the  secondary  axes,  and 
so  on.  The  flowers  thus  develop  in  basipetal  (centrifugal)  order.  From 
the  fact  that  every  axis  is  terminated  by  a  flower,  such  clusters  are 
often  called  determinate.  This  distinction  into  indeterminate  and  deter- 
minate is,  however,  a  misleading  one,  for  some  botryose  inflorescences 
are  in  fact  determinate — e.g.,  the  Umbel  and  Head  ;  while,  on  the  other 
hand,  most  of  the  cyrnoge  flower  clusters  are  capable  of  indefinite  ex- 
tension, as  is  notably  the  case  witli  the  Helicoid  and  Scorpioid  forms 
It  not  infrequently  happens  that  in  large  flower  clusters  a  part  of  the 
branching  is  of  one  type  and  the  remainder  of  the  other  ;  all  such  cases 
may  be  considered  as  examples  of  mixed  inflorescence. 

The  most  important  of  the  terms  in  common  use  are  given  in  the 
following  table  of  inflorescences  : 

A.  BOTRYOSE  INFLORESCENCE. 

I.  Flowers  solitary  in  the  axils  of  the  leaves — 

e.g.,  Vinca Solitary  Axillary. 

II.  Flowers  in  simple  groups. 

1.  Pedicellate. 

(a)  On  an  elongated  axis  :  pedicels  about 

equal— e.g.,  Mignonette Raceme. 

(6)  On  a  shorter  axis  ;  lower  pedicels 

longer— e.g.,  Hawthorn Corymb. 

(c)  On  a  very  short  axis  ;  pedicels  about 

equal— e.g.,  Cherry Umbel. 

2.  Sessile. 

(a)  On  an  elongated  axis — e.g.,  Plantain.Spike. 
Var.  ft.  Drooping,  and  scaly  bracted— 

e.g..  Poplar Catkin. 

Var.  y.  Thick  and  fleshy-e.gr.,  Indian 

Turnip Spadix. 

(6)  On  a  very  short  axis— e.g.,  Clover. .  .Head- 
Ill.  Flowers  in  compound  groups. 
1.  Regular. 

(a)  Racemes  in  a  raceme—  e.g.,S}nilatina.Com-pound  Raceme. 

(b)  Spikes  in  a  spike— e.g. ,  Wlieal Compound  Spike. 

(r)  Umbels  in  an  umbel—*./?.,  Parsnip.. Compound.  Umbel. 


GLOSSOLOGY  OF  ANGIOSPERMS.  429 

(d)  Heads  in  a  raceme — e.g.,  Ambrosia.  .Heads  Racemose. 

(e)  Heads  in  a  spike— e.g.,  Liatris Heads  Spicate. 

And  so  on. 

2.  Irregular. 

Racemosely  or  corymbosely  compound — 

e.g.,  Cutalpa Panicle. 

Compound  forms  of  the  panicle  itself  are  common — e.g.,  panicled 
heads  in  many  Composite,  panicled  spike*  in  many  grasses. 

B.  CYMOSE  INFLORESCENCE. 

I.  Flowers  solitary  ;   terminal — e.g.,  Anemone 

nemorosa Solitary  Terminal. 

II.  Flowers  in  clusters  (Cymes). 

1.  Lateral  branches  in  all  parts  of  the  flower 

cluster  developed — e.g.,  Cerastium Forked     Cyme,     or 

Dichasium. 
(This  is  the  Biparous,  and  so-called  Dichotomous  Cyme  of  authors.) 

2.  Some  of  the  lateral  branches  regularly  suppressed. 

(a)  The  suppression  all  on  one  side — e.g., 

Hemerocallis Helicoid    Cyme,   or 

Bostryx. 
(6)  The  suppression  alternately  on  one 

side  and  the  other — e.g. ,  Drosera. . .  Scorpioid  Cyme,  or 

Cicinnus. 

(The  last  two  are  frequently  not  distinguished  from  one  another,  and 
are  called  Monochasia,  Uniparous  Cymes,  or  False  Racemes.) 

O.  MIXED  INFLORESCENCE. 

1.  Cymo-Botryose,  in  which  the  primary  in- 

florescence  is    botryose,   while   the  sec- 
ondary is  cymose,  as  in  Horsechestnut. .  . Cymo-Botry s. 
(This  is  sometimes  called  a  Thyrsus.) 

2.  Botryo-Cf/mose,  in  which  the  primary  in- 

florescence is  cymose,  while  the  sec- 
ondary is  botryose — e.^.,inmany  Com- 
posite  Botry-Cyme. 

Floral  Symmetry. — The  parts  of  the  flower  are  mostly  arranged 
in  whorls,  which  are  distinctly  separated  from  each  other  (cyclic  flow- 
ers) ;  in  some  cases  they  are  arranged  in  spirals,  with,  however,  a  dis- 
tinct separation  of  the  different  groups  of  organs  (Jiemicyclic  flowers) ; 
in  still  other  cases  the  arrangement  is  spiral  throughout,  with  no 
separation  of  the  groups  of  organs  (acyclic  flowers). 


430  EOT  A  NT. 

In  cyclic  flowers  there  are  most  frequently  four  or  five  whorls,  viz.  . 

1.  The  Calyx,  composed  of  (mostly)  green  sepals. 

2.  The  Corolla,  composed  of  (mostly)  colored  petals. 

3.  (4.)  The  Andioecium,  composed  of  one  or  two  whorls  of  stamens. 
4  or  5.  The  Gyncecium,  composed  of  carpels. 

These  whorls  usually  contain  definite  numbers  of  organs  in  each  ;  in 
many  cases  the  numbers  are  the  same  for  all  the  whorls  of  the  flower 
(i&omerous  flower) ;  when  the  numbers  are  different  the  flower  is  said 
to  be  heteromerous. 

The  terms  which  denote  these  numerical  relations  are  :  monocyclic, 
applied  to  a  flower  having  only  one  cycle  ;  bicydic,  two  cycles  ;  tricydic, 
three  cycles ;  tetracydic,  four  cycles  ;  pcnta  yclic,  five  cycles,  etc.  ; 
monomerous,  applied  to  flowers  each  cycle  of  which  contains  one  mem- 
ber ;  dimerous,  two  members  ;  trimerous,  three  members  ;  tetramercus, 
four  members  ;  pentamerous,  five  members. 

These  relations  can  be  briefly  indicated  by  using  symbols  and  con- 
structing floral  formulae,  as  follows  : 

Ca5,  CoB,  An5,        Qn5  =  a  tetracyclic  pentamerous  flower  ; 

Ca3,  Co3,  An3  +  3,  Gns  =  a  pentacyclic  triiuerous  flower. 
Most  commonly  the  members  of  one  whorl  alternate  with  those  of 
the  whorls  next  above  and  below ;  in  a  few  cases,  however,  they  are 
opposite  (or  superposed)  to  each  other.  These  relations  may  be  indi- 
cated by  a  modification  of  the  floral  formulae  given  above,  as  follows, 
where  the  members  are  alternate  : 


Gn 
An 
An 
Co 
Ca 
B 


When  they  are  opposite  the  arrangement  is  as  follows  : 
Gn     --     -     -     - 


Co 

Ca 

B 


In  both  these  formulae  the  position  of  the  parts  of  the  flower  with 
respect  to  the  flowering  axis  is  indicated  by  the  position  of  the  bract 
B,  which  is  always  on  the  anterior  side,  while  the  axis  is  always  pos- 
terior. 

When  all  the  members  on  each  whorl  are  equally  developed,  having 
the  same  size  and  form,  the  flower  may  be  vertically  bisected  in  any 
plane  into  two  equal  and  similar  halves;  it  is  then  actinomorpMc 
(=  regular,  and  pulysymmetrical).  When  the  members  in  each  whorl 


GLOSSOLOGY  OF  ANGIOSPERMS.  431 

are  unlike  in  size  and  form,  and  the  flower  is  capable  of  bisection  in 
only  one  plane,  it  is  zygom-n phic  (=  irregular,  and  monosyminetrical). 
In  the  latter  there  is  generally  more  or  less  of  an  abortion  of  certain 
parts — i.e.,  one  or  more  of  the  sepals,  petals,  stamens,  or  pistils  are  but 
partially  developed,  appealing  in  the  flower  as  rudiments  only.  Some- 
times this  is  BO  marked  as  to  result  in  the  complete  suppression  of  cer- 
tain parts. 

It  not  infrequently  happens  in  both  actinomorphic  and  zygomorphic 
flowers  that  entire  whorls  are  suppressed  ;  this  gives  rise  to  a  number 
of  terms,  as  follows  : 

When  all  the  whorls  are  present  (not  necessarily,  however,  all  mem- 
bers of  all  the  whorls)  the  flower  is  said  to  be  complete  ;  when  one  or 
more  of  the  whorls  are  suppressed,  the  flower  is  incomplete. 
As  to  its  perianth,  the  flower  is  said  to  be 

Dichlamydeous,  when  both  the  whorls  of  the  perianth  are  present , 
Monochlamydeous,  when  but  one  (usually  the  calyx)  is  present ; 
Apetalous,  when  the  corolla  is  wanting  ; 

Achlamyde^us,  or  naked,  when  both  calyx  and  corolla  are  wanting ; 
As  to  its  sexual  organs,  the  flower  is 

Bisexual  (or  hermaphrodite)  when  stamens  and  pistils  are  present  ; 
Unisexual,  when,  of  the  essential  organs,  only  the  stamens  are  pres- 
ent (then  staminate),  or  only  the  pistils  (then  pistillate) ; 
Neutral,  when  both  stamens  and  pistils  are  wanting  ; 
Collectively,  bisexual  flowers  are  said  to  be  mon1  clinous  ;  unisexual 
flowers,  diclinous  ;  while  in  those  cases  where  some  flowers  are  bisex- 
ual and  others  unisexual  they  are,  as  a  whole,  said  to  be  polygamous. 
Diclinous  flowers  are  further  distinguished  into 
Mon&cious,  when  the  staminate  and  pistillate  flowers  occur  on  the 

same  plant,  and 

Dmcious,  when  they  occur  on  different  plants. 

The  Perianth.— In  a  large  number  of  flowers  the  parts  of  the 
calyx  and  corolla  (sepals  and  petals)  are  distinct — i.e..  not  at  all  united 
to  one  another  ;  such  are  said  to  be  chorisepaloun*  as  to  the  calyx,  and 
choripetalous  as  to  the  corolla.  The  terms  polysepalous  and  polypttal- 
i.us  are  the  ones  most  commonly  used  in  English  and  American  books 
on  botany,  although  they  manifestly  ought  to  be  used  as  numerical 
terms.  Eleutheropetalous  f  and  dialypetalous  \  are  also  somewhat  used, 
especially  in  German  works. 
The  numerical  terms  usually  employed  are  mono-,%  di-,  tri-,  tttra-, 

*  From  Greek  ^up/feiv,  to  sever,  to  separate. 

f  From  Greek  efcvQepos,  free. 

J  From  Greek  Atahvetv,  to  part  asunder. 

§  The  terms  moncsepalous  and  monopetalous  were  formerly  used  with 
a  different  meaning  from  that  given  here  ;  they  were  applied  to  the 
forms  now  called  gamosepalous  and  gamopetalous.  This  use,  errone- 


432  BOTANY. 

penta-sepalovs,etc.,  and  mono-,  di-,  tri-,  tetra-,  p-nta-petalom,  etc.,  mean- 
ing of  one,  two,  three,  four,  five  sepals  or  petals  respectively.  Polysepa- 
lous  &nApolypetalous  are  properly  used  to  designate  "  a  considerable  but 
unspecified  number  "  of  sepals  or  petals.* 

In  some  flowers  the  sepals  or  petals,  or  both,  are  united  to  one 
another,  so  that  the  calyx  and  corolla  are  each  in  the  form  of  a  single 
tube  or  cup.  This  union  of  similar  parts  is  called  coalescence.  The 
terms  gamosepalous  f  and  gamopc to,  ous  (or  synipe talous)  are  used  in  such 
cases.  Monosepalous  and  monopetalous,  still  used  in  this  sense  in  many 
descriptive  works,  should  be  reserved  for  designating  the  number  of 
sepals  or  petals  in  calyx  and  corolla  respectively. 

Not  infrequently  the  calyx  and  corolla  are  connately  united  to  each 
other  for  a  less  or  greater  distance.  This  union  of  dissimilar  whorls  is 
termed  adnation,  and  the  calyx  and  corolla  are  said  to  be  adnate  to 
each  other. 

The  Andrcecium. — The  number  of  stamens  in  the  flower  or  the 
andro3cium  is  indicated  by  such  terms  as 

Monandrous,  signifying  of  one  stamen  ; 

Diandrous,  of  two  stamens ; 

Triandrous,  of  three  stamens ; 

Tetrandrous,  of  four  stamens — when  two  of  the  stamens  are  longer 
than  the  other  two,  the  androecium  is  said  to  be  didynamoui ; 

Pentandrous,  of  five  stamens ; 

Htxandrous,  of  six  stamens  ;  when  four  are  longer  than  the  remain- 
ing two,  the  androecium  is  said  to  be  tetradynamous. 

Other  terms  of  similar  construction  are  used,  as  heptandTOUS,  seven 
stamens  ;  octandrous,  eight ;  enneand  ous,  nine  ;  decandrous,  ten  ;  dodec- 
androus,  twelve ;  and  polyaitdrous,  many  or  an  indefinite  number  of 
stamens. 

The  stamens  may  be  in  a  single  whorl  (monocydic),  in  which  case,  if 
agreeing  in  number  with  the  rest  of  the  flower,  the  androecium  is  said 
to  be  isostemonous  ;  they  are  often  in  two  whorls  (by cyclic),  and  when 
each  whorl  agrees  with  the  numerical  plan  of  the  flower,  the  androe- 
cium is  diplostemonom. 

The  various  kinds  of  coalescence  require  the  use  of  special  terms. 
When  there  is  a  coalescence  of  the  filaments  the  androscium  is 

Monadelphous,  when  the  stamens  are  united  into  one  set ; 

Diadelphous,  when  united  into  two  sets  ; 

Triadelphous,  when  united  into  three  sets,  etc. 

ous  as  it  obviously  is,  has  not  yet  been  abandoned  in  works  on  descrip- 
tive botany. 

*  Dr.  Gray  throws  the  weight  of  his  authority  in  favor  of  this  use  of 
these  terms  ("Structural  Botany,"  1879,  p.  244). 

f  From  Greek  yu/^oS,  union. 


GLOSSOLOGY  OF  ANGIOSPERMS.  433 

When  there  is  a  coalescence  of  the  anthers  the  androacium  is  ayn- 
genesious  or  synantherous.  f 

The  stamens  may  be  adnate  to  the  petals,  when  they  are  epipetalous  ; 
in  some  cases  they  are  adnate  to  the  style  of  the  pistil,  as  in  the 
Orchids ;  such  are  said  to  be  yynandrous. 

The  principal  terms  which  designate  the  structural  relation  between 
the  anther  and  filament  in  individual  stamens  are  : 

Adnate,  applied  to  anthers  which  are  adherent  to  the  upper  or  lower 
surface  (anterior  or  posterior)  of  the  filament  ;  when  on  the  upper 
surface  the  anthers  are  introrse  ;  when  on  the  lower,  extrorse. 

Innate,  applied  to  anthers  which  are  attached  laterally  to  the  upper 
end  of  the  filament,  one  lobe  being  on  one  side,  the  other  on  the  oppo- 
site one.  The  part  of  the  filament  between  the  two  anther-lobes  is 
designated  the  connective  /  it  is  subject  to  many  modifications  of  form, 
and  often  becomes  separable  by  a  joint  at  the  base  of  the  anther  from, 
the  rest  of  the  filament. 

Versatile  is  applied  to  anthers  which  are  lightly  attached  to  the  top 
of  the  filament,  so  as  to  swing  easily  ;  these  may  also  be  introrse  or 
extroise. 

The  Gyncecium. — The  Qynoecium  is  made  up  of  one  or  more  carpels 
(carpids  or  carpophylld) — i.e.,  ovule-bearing  phyllome^,  and  it  is  said  to 
be  mono-,  di-,  tri-,  tetra-,  penta-,  etc.,  and  poly  carpettary,  according  as  it 
has  one,  two,  three,  four,  five,  to  many  carpels.  In  old  books  the 
terms  monogynous,  digynous,  trigynous,  etc. ,  meaning  of  one,  two,  three, 
etc.,  carpels,  are  used  instead  of  the  more  desirable  modern  ones.  When 
the  carpels  are  more  than  one  they  may  be  distinct,  forming  the  apo- 
carpous gyncecium  ;  or  they  may  be  coalescent  into  one  compound  or- 
gan, the  syncarpous  gynoecium.  In  the  former  case  the  term  pistil  is 
applied  to  each  carpel,  and  in  the  latter  to  the  compound  organ.  Pis- 
tils are  thus  of  two  kinds,  simple  and  compound  ;  the  simple  pistil  is 
synonymous  with  carpel  ;  the  compound  pistil  with  syncarpous  gynce- 
cium. 

In  the  simple  pistil  the  ovules  actually  grow  out  from  the  united 
margins  (the  ventral  suture)  of  the  carpophyllum  ;  the  internal  ridge  or 
projection  upon  which  they  are  borne  is  the  placenta.  Sometimes  the 
ovules  are  erect — i.e.,  they  grow  upward  from  the  bottom  of  the  ovary — 
and  when  single  appear  to  be  direct  continuations  of  the  flower  axis 
(Fig.  304).  Suspended  ovules— i.e. ,  those  growing  from  the  apex  of  the 
ovary  cavity — are  also  common. 

In  compound  pistils  the  coalescence  may  be,  on  the  one  hand,  of  closed 
carpels,  and  on  the  other  of  open  carpels.  In  the  former  case  the  pis- 
til has  generally  as  many  loculi  (cavities  or  cells)  as  there  are  carpels  ; 
this  is  expressed  by  the  terms  uni-,  U-,  tri-,  quadri-,  and  so  on  to  multi- 
locular.  Such  pistils  have  axtte  placentae— i.e. ,  they  are  gathered 
about  the  axis  of  the  ovary,  e.g.,  Hypericum.  In  the  case  of  compound 
pistils  formed  by  the  coalescence  of  open  carpels,  the  margins  only  of  the 


434  BOTANY. 

latter  unite,  forming  a  common  ovary  cavity  ;  here  the  placentae  gener- 
ally occur  along  the  sutures,  and  are  said  to  be  parietal — i.e.,  on  the 
walls.  Between  such  unilocular  pistils  and  the  uiultilocular  ones 
described  above  there  are  all  intermediate  gradations.  In  one  series  of 
gradations  the  placentae  project  farther  and  i'arther  into  the  ovary  cav- 
ity, at  last  meeting  in  the  centre,  when  the  pistil  becomes  multilocular 
with  axile  placentae.  On  the  other  hand,  a  multilocular  pistil  sometimes 
bt  comes  unilocular  by  the  breaking  away  of  the  partitions  during 
growth.  In  such  a  case  the  placentae  form  a  free  central  column, 
commonly  called  nfree  central  placenta. 

In  other  cases  a  free  placental  column  of  an  entirely  different  origin 
occupies  tlie  axis  of  a  unilocular,  but  evidently  polycarpellary  pistil. 
In  Anagallis,  ior  example,  the  placental  column  grows  from  the  base 
of  the  ovary  cavity,  and  there  is  at  no  time  a  trace  of  partitions  (see 
illustrations  of  the  Order  Primulacese,  p.  507). 

The  Qyno3cium  may  be  free  from  all  the  other  organs  of  the  flower, 
which  are  then  said  to  be  liypoyynous*  and  the  gynoecium  itself  su- 
perior. Sometimes  the  growth  of  the  broad  flower-axis  stops  at  its 
apex  long  before  it  does  so  in  its  marginal  portions  ;  a  tubular  ring  is 
thus  formed,  carrying  up  calyx,  corolla,  and  stamens,  which  are  then 
said  to  be  perigynous,^  and  the  gyncecium  half  inferior.  These  terms 
are  used  also  in  the  cases  where  the  gyncecium  is  similarly  surrounded 
by  the  tubular  sheath  composed  of  adnate  calyx,  corolla,  and  androe- 
cium.  In  some  nearly  related  cases,  in  addition  to  the  structures  de- 
scribed above  as  perigynous,  there  is  a  complete  fusion  of  the  calyx, 
corolla,  and  stamen -bearing  tube  with  the  gynoecium,  so  that  the  ovule- 
bearing  portion  of  the  latter  is  below  the  rest  of  the  flower,  e.g.,  Com- 
positae.  The  perianth  and  the  stamens  are  said  to  be  epiyynom\  in  such 
ilowers,  and  the  ovary  is  inferior.  Some  cases  of  epigyny  are  doubtless 
to  be  regarded  as  due  to  the  adnation  of  the  calyx,  eorolla,  stamens, 
and  ovaries  ;  in  others,  the  ovaries  are  adnate  to  the  hollow  axis  which 
bears  the  perianth  and  stamens  ;  in  still  others,  it  seems  probable  that 
the  hollow  axis  is  itself  ovule-bearing,  and  that  the  true  carpels  are 
borne  on  its  summit. 

Certain  terms  descriptive  of  relations  between  the  stamens  and  pis- 
tils which  have  recently  come  into  use  require  explanation  here. 

In  many  flowers  the  stamens  and  pistils  do  not  mature  at  the  same 
time,  such  are  said  to  be  dichogamous ;  when  the  stamens  mature  be- 
fore the  pistils  the  flower  is  proterandrous  ;  and  when  the  pistils  ma- 
ture before  the  stamens  they  are  proterogynous. 

In  some  species  of  plants  there  are  two  or  three  kinds  of  flowers, 

*  From  Greek  into,  under,  and  yvvrj,  female — i.e.,  the  pistil, 
f  From  the  Greek  nepi,  about,  etc. 
|  From   the  Greek  i-xl,  upon,  etc. 


GLOSSOLOGY  OF  ANGIOSPERMS.  435 

differing  as  to  the  relative  lengths  of  the  stamens  and  styles  ;  these  are 
called  heterogonovs*  or  heterostyled.  When  there  are  two  forms,  viz., 
one  in  which  the  stamens  are  long  and  the  styles  short,  and  the  other 
with  short  stamens  and  long  styles,  the  flowers  are  said  to  be  dimorph- 
ova,  or  more  accurately  luterogonous  dimurpttous,  and  the  forms  are 
distinguished  as  s?i  rt-styled  and  I  ng-s'y  ed  When,  as  in  some  spe- 
cies of  Oxalis,  there  are  three  forms,  viz.,  long-,  mid-,  and  short-styled, 
the  term  trimorphous  (or  better  heterogon,i,us  tiimorph'iu-)  is  used. 

The  Fruit.— The  fruit  may  include  (1)  only  the  ripened  ovary  with  its 
contained  seeds — eg.,  the  bean  ;  or  (2)  these  with  an  adnate  calyx  or  re- 
ceptacle— e.g.,  the  apple.  Many  changes  frequently  take  place  in  ripen- 
ing, such  as  (1)  an  increase  in  the  number  of  cells  by  the  formation  of 
false  partitions,  or  (2)  a  decrease  in  their  number  by  the  obliteration  of 
some  ;  (3)  the  growth  of  wings  or  prickles  upon  the  exterior  of  the  ovary  ; 
(4)  the  thickening  and  formation  of  a  sot  and  juicy  pulp;  (5)  the 
hardening  of  some  portions  of  the  ovary  wall  by  the  development  of 
sclerenchyma ;  (6)  the  thickening  and  growth  of  the  calyx  or  recep- 
tacle. 

In  cases  where  in  the  ripening  the  ovary  walls  remain  thin,  and 
eventually  become  dry,  the  fruits  are  said  to  be  dry — e.g.,  in  the  bean  ; 
where  the  walls  become  thickened  and  more  or  less  pulpy,  they  are 
fleshy — e. 9.,  the  peach.  These  terms  are  also  used  in  reference  to  the 
fruit  when  it  includes  an  adnate  calyx  or  receptacle.  In  many  fleshy 
fruits  (developed  from  carpels)  the  inner  part  of  the  pericarp  wall  is 
hardened  ;  the  two  layers  are  then  distinguished  as  txocarp  and  endv- 
curp ;  when  there  are  three  layers  the  middle  one  is  the  men(C  rp. 

The  opening  of  the  fruit  in  order  to  permit  the  escape  of  the  seeds  is 
called  its  defiis-ence,  and  such  fruits  are  said  to  be  dehiscent;  those 
which  do  not  open  are  ind'hi\fenf..  In  fruits  developed  from  single 
carpels  dehiscen'ce  is  generally  through  the  ventral  or  dorsal  suture,  or 
both  ;  in  those  developed  from  compound  pistils  the  partitions  may 
split,  and  thus  resolve  each  fruit  into  its  original  carpels  (septicidal 
dehiscence) ;  or  the  dorsal  sutures  may  become  vertically  ruptured, 
thus  opening  every  cell  (loculus)  by  a  vertical  slit  (loculicidal  d<hi<- 
ceice).  Among  the  other  forms  of  dehiscence  only  that  called  circum- 
cimle  and  the  in;gular  need  be  mentioned  ;  in  the  former  a  transverse 
slit  separates  a  lid  or  cap,  exposing  the  seeds  ;  in  the  latter  an  irregu- 
lar slit  forms  at  a  certain  place,  and  through  this  the  seeds  escape. 

The  principal  fruits  may  be  distinguished  by  the  brief  characters 
given  in  the  following  table  :f 

*  Proposed  by  Dr.  Gray,  Am.  Naturctiiol,  Jan.,  1877. 

f  This  is  based  upon  Dr.  Dickson's  classification  as  modified  by 
Professor  Balfour  in  the  article  "Botany  "  in  the  ninth  edition  of  the 
"  Encyclopedia  Britannic..,"  Vol.  IV.,  p.  153. 


436  BOTANY. 

A.  Monogyncecial  fruits,  formed  by  tlie  gynoecium  of  one  flower. 

I.  Capsulary  fruits.     Dry,  dehiscent,  formed  from  one  pistil. 

1.  Monocarpellary. 

(a)  Opening  by  one  suture — e.g  ,  Cnltha FOLLICLE. 

(b)  Opening  by  both  sutures — eg.,Pm LEGUME. 

2.  Bi-polycarpellary — e.g.,  Viola CAPSULE. 

Var.  a.  Dehiscence  circumcissile — i\g.,  Ana- 
galds Pyxis. 

Var.  b.  Dehiscence  by  the  falling  away  of 
two  lateral  valves  from  the  two  per- 
sistent parietal  placentae  —  e.g.,  Mus- 
twd Silique. 

II.  Schizocarpic  fruits.     Dry,  breaking  up  into  one-celled  inde- 
hiscent  portions. 

1.  Monocarpellary,  dividing  transversely — e.g.,  Des- 

modium LOMENT. 

2.  Bi-polycarpellary. 

(a)  Dividing  into  achene-like  or  nut-like  parts 

(nutlet*),  no  forked  carpophore — e.g.,  Lith- 

ospeimum. CARCERULUS. 

(b)  Dividing  into  two  achene-like  parts  (meri- 

ca  ps),  a  forked  carpophore  between  them 

— e.g.,  Uinbelliferae, CREMOCARP. 

III.  Achenial  fruits.     Dry,  indehiscent,  one  celled,   one   or   few 
seeded,  not  breaking  up. 

1.  Pericarp  hard  and  thick— e.g.,  Oak NUT. 

2.  Pericarp  thin— e.g.,  Sunflower ACHENE. 

Var.  a.  Pericarp  loose  and  bladder-like — e.g., 

(JhenopoHium Utricle. 

Var.  b.  Pericarp  consolidated  with  the  seed — 

e.g.,  Grasses Caryopeis. 

Var.  c.  Pericarp  prolonged  into  a  wing — e.g., 

Ash Samara. 

IV.  Baccate  fruits.     Fleshy,  indehiecent  ;  seeds  in  pulp. 

1.  Rind  firm  and  hard— e.g. ,  Pumpkin PEPO. 

2.  Rind  thin— e.g.,  Goosebeny BERRY. 

V.  Drupaceous  fruits.     Fleshy,  indehiscent ;  endocarp  indurated, 
usually  stony. 

1.  One  stone,  usually  one-celled— e.g.,  Cherry DRUPE. 

2.  Stones  or  papery  carpels,   two  or  more— e.g., 

Apple POME. 

VI.  Aggregate  fruits.     Poly  carpel  1  a  ry  ;  carpels  always  distinct. 
The  forme  of  these  are  not  well  distinguished.     In  many  Ranuncu- 


TISSUES  OF  ANGI08PERM8.  437 

laceae  there  are  numerous  achenes  on  a  prolonged  receptacle  ;  in  Mag- 
nolia numerous  follicles  are  similarly  arranged  ;  in  the  raspberry  many 
drupelets  cohere  slightly  into  a  loose  mass,  which  separates  at  maturity 
from  the  dry  receptacle  ;  in  the  blackberry  similar  drupelets  remain 
closely  attached  to  the  fleshy  receptacle ;  in  the  strawberry  there  are 
many  small  achenes  on  the  surface  of  the  fleshy  receptacle  ;  finally,  in 
the  rose  several  to  many  achenes  are  enclosed  within  the  hollow  and 
somewhat  fleshy  receptacle. 

B.  Polygynaxinl  fruits,  formed  by  the  gynoecia  of  several  flowers. 

1.  A  spike  with  fleshy  bracts  and  perianths — e.g., 

Mulberry SOROSIS. 

2.  A   spike  with  dry   bracts  and   perianths — e.g., 

Birch STROBILE. 

3.  A  concave  or  hollow,  fleshy  receptacle,  enclosing 

many  dry  gynoecia — e.g.,  Fig SYCONUS. 

The  Seed. — Many  of  the  terms  used  in  the  description  of  the  ovule 
are  applied  also  to  the  seed.  However,  the  modifications  which  most 
of  the  parts  undergo  render  necessary  some  additional  terms.  Thus 
the  outer  integument  is  generally  so  thickened  and  hardened  that  it  is 
commonly  called  the  testa.  The  inner  is  sometimes  called  tlie  tegmen. 
In  some  seeds  the  outer  coat  becomes  fleshy,  in  which  case  they  are 
baccate  (berry-like)  ;  in  others  the  outer  part  of  the  testa  is  fleshy  and 
the  inner  hardened,  so  that  the  seed  is  drupe-like  (drupaceous).  Occa- 
sionally an  additional  coat  forms  around  the  ovule  after  fertilization; 
it  differs  somewhat  in  nature  in  different  plants,  but  all  are  commonly 
included  under  the  name  aril — e.g.,  May  Apple. 

The  testa  may  be  prolonged  into  one  or  more  flat  extensions  ;  such  a 
seed  is  winged — e.g.,  Catalpa.  Its  epidermal  ct  11s  may  be  prolonged 
into  trichomes,  forming  the  comose  seed — e.g.,  cotton. 

The  embryo  either  occupies  the  whole  of  the  seed  cavity,  in  exalbu- 
minous  seeds,  or  it  lies  in  or  in  contact  with  the  endosperm,  in  the 
albuminous  seeds.  It  is  straight — e.g.,  the  pumpkin;  or  variously 
curved  and  folded — e.g.,  in  Erysimum,  where  the  cotyledons  are  in- 
cumbent, and  in  Ardbis,  where  they  are  accumbent. 

537.— The  Tissues  of  Angiosperms. — The  epidermis  of 
Angiosperms  does  not  differ  in  any  marked  way  from  that 
of  the  Gymnosperms  and  the  Pteridophytes.  The  principal 
differences  are  that,  as  a  rule,  the  stomata  are' more  numer- 
ous, and  the  trichomes,  which  are  much  more  commonly 
present,  show  greater  variations  in  form  and  structure.  It 
is  noticeable,  furthermore,  that  in  both  these  points  the 
Dicotyledons  excel  the  Monocotyledons. 


438  BOTANY. 

538. — The  tissues  of  the  fundamental  system  in  the  An- 
giosperms  are,  in  general,  sharply  set  off  from  those  of 
the  epidermal  and  fibre-vascular  systems.  In  the  annual 
stemmed  species  the  fundamental  tissues  constitute  the  great- 
er part  of  the  stems,  but  in  perennial-stemmed  species  there 
is  proportionately  le?s  of  these,  and  more  of  the  fibro-vascular 
tissues  ;  in  the  former  the  principal  tissue  in  the  funda- 
mental system  is  parenchyma,  which  occupies  the  interfascic- 
ular  spaces,  as  well  as  the  greater  part  of  that  lying  between 
the  bundles  and  the  epidermis — i.e.,  in  the  cortical  region. 
In  perennials,  on  the  contrary,  the  interfascicular  spaces  are 
in  many  cases  occupied  by  sclerenchyma,  and  the  cortical 
region  either  entirely  disappears  (as  in  Dicotyledons)  or  it 
becomes  filled  with  sclerenchymatous  or  fibrous  tissue. 

In  the  leaves  the  fundamental  system  rarely  includes  more 
than  chlorophyll-bearing  parenchyma,  while  in  the  parts  of 
flowers  a  similar  tissue  is  found,  which  is,  however,  generally 
wanting  in  chlorophyll.  The  succulent  parts  of  fruits, 
whether  phyllome  or  caulome  structures,  are  composed  of 
parenchyma  of  the  fundamental  system. 

539. — The  fibro-vascular  bundles  of  the  stems  of  Angio- 
sperms  are  entirely  of  De  Bary's  "collateral"  class — that  is, 
each  bundle  in  cross-section  presents  more  or  less  distinctly 
two  sides,  viz.,  xylem  and  phloem.  Each  of  these  sides,  as 
previously  described  (paragraph  147),  generally  contains 
parenchymatous,  fibrous,  and  vascular  tissues,  the  latter 
tracheary  in  the  xylem,  and  sieve  in  the  phloem. 

540. — The  disposition  of  the  bundles  in  the  Angiosperms 
is  for  the  most  part  dependent  upon  the  position  of  the  leaves. 
Nearly  all  the  first-formed  bundles  are  of  the  kind  termed 
"common  bundles" — that  is,  they  extend  on  the  one  hand 
into  the  leaf,  and  on  the  other  down  into  the  stem.  In 
Fig.  314  there  pass  down  from  each  leaf  three  bundles ;  at 
the  lower  int'ernode  these  are,  on  the  left,  a,  b,  c,  and  on  the 
right,  d,  e,  f.  At  the  next  internode,  where  the  leaves 
stand  at  right  angles  to  the  lower  ones,  there  are  three 
bundles  again,  g,  h,  /,  and  k,  I,  m  ;  these  are  largest  at  their 
points  of  curvature,  and  they  dwindle  in  size  as  they  pass 
downward  and  finally  unite  with  the  bundles  from  the  lower 


TISSUES  OF  ANQ1O8PERM8. 


439 


.—Showing  the  disposition  of  the  fibro- vascular  bundles  in  the  stem  of  Clem- 
lla  a,  ft,  c,-d,  e,f,  the  bundle*  f  om  the  lower  pair  of  leaves;  a,  h  i  - 
e  bundles  from  the  second  pair  of  leaves  ;  n,  o.  p,-q,  r,  «,  the  bundles 
third  pair  of  leaves  ;  a-  and  t,  the  median  bundle's  ol  the  fourth  pair  of 
0,  —  y,  6,  pairs  of  rudimentary  leaves  not  yet  supplied  with  bundles  - 


«•»  •">  •     »    ^"^    "««»w»^"    ..»,.««    »,,»v,    K-V.^WIJVI    yo.ii    IM    icavt-p.  ,     /(,    f/,  //    — q     y    *    |,fj^    hlllii.l 

from  the  third  pair  of  leaves  ;  x  and  /,  the  median  bundles  of  the' fourth  pair  < 
I<M\  es  ,  n,  (i,  —  y,  (>,  pairs  of  nuUmeutarir  leaves  not  yet  supplied  with  bundle* 
After  Nageli. 


atu  Ttticdla 
K,l,m,  the 


440 


BOTANY. 


pair  of  leaves.  The  bundles  from  the  third  internode  pass 
downward,  and  in  like  manner  join  those  from  the  second 
pair  of  leaves,  and  so  on.  Thus  in  such  a  stem  every  bundle 

passes  downward 
through  one  in- 
ternode before 
joining  another, 
and  in  any  inter- 
node all  the  bun- 
dles are  derived 
from  the  leaves  at 
its  summit. 

In  Fig.  315, 
with  a  similar  ar- 
rangement in  the 
main,  there  are 
some  complica- 
tions. The  lateral 
leaf-bundles  (b,  c 
in  the  lower  inter- 
node, and  g,  h  in 
the  next  one)  pass 
downward  to  the 
next  node,  where 
they  unite  with 
other  descending 
bundles  ;  and  the 
median  bundles, 

a>f>  1)  °}  r>  u>  Pa'c's 

down  through  two 
internodes,  a  n  d 
then  fork  right 
and  left,  a  n  d 
unite  with  other 
descending  bun- 
dles. Thus  in 
any  intornode  there  are  bundles  from  at  least  three  leaves. 
This  is  shown  in  the  cross-section  of  the  next  to  the  lower 
internode  (Fig.  316),  in  which  the  bundles  A,/,  (/,  k,  i  pass 


Fig.  815.—  Diagram  showing  the  arrangement  < 
flbro-vaecular  bundles  in  the  stem  of  Lathi/rw<  Ptoeuda- 
phaea.  The  bundle*  nearest,  the  obi-crv.  r  are  figured  dark- 
er, those  farthest  away  lighter. -After  Nageli. 


TISSUES  OF  ANG10  SPERMS. 


441 


Fig.  316.  —  Cross-sec- 
tiou  of  the  next  to  the 
lower  internode  of  Fig. 
315,showingthe  arrange- 
ment of  the  bundles,  the 
lettering  as  in  Fig.  315. 
—After  Nageli. 


into  the  second  leaf — i.e.,  the  leaf  at  the  summit  of  the  iu- 

ternofle  under  consideration  ;  the  bundles 

/,  m,  n  descend  from  the  leaf  next  above, 

and  j9  and  q  from  the  one  still  higher. 
541. — We  may  get  a  clearer  idea  of  the 

mutual  relations  of  the  bundles  if  we  con- 
ceive the  bundle-cylinder  to  be  split  down 

on  one  side,  and  spread  out  upon  a  plane. 

In  Fig.  317  we  have  such  a  diagrammatic 

representation  of  the  arrangement  of  the 

bundles  in  the  stem  of  Stachys  anyusti- 

folius.     Here  each  leaf  sends  down  two 

bundles,  which  pass  through  two  internodes  and  then  unite 
with  other  descending  bundles  at 
their  middle  points.  The  fibro- 
vascular  cylinder  is  thus  compos- 
ed when  complete  of  repeatedly 
branching  bundles.  A  cross-sec- 
tion (Fig.  318)  through  the  stem 
at  some  distance  above  the  lower 
leaves  in  Fig.  317 
shows  that  each 
internode  c  o  n  - 
tains  bundles 
from  two  pairs  of 
leaves — i.e.,  those 
at  its  summit  and 
those  at  the  sum- 
mit of  the  one 
above.  In  Fig. 
318  the  pairs  of  gel', 
bundles  marked  c  and  d  descend 
from  the  leaves  c  and  d,  while 
those  marked  e  and/  pass  down 
from  the  leaves  one  internode 

Fig:.  317.— Diagram  showing  the  ar-  higher  up. 
iingernent  of  tho  fibro-vascular  bun-         T  •      M      i  n     -,- 

dies  in  stadiys  antfuttifoiiw.  a,  b,      In  a  similarly  constructed  dia- 


/"  \ 


i 


_  318.  —  Cross- 
tion  of  the  next 
to  the  lower  inter- 
node in  Fig.  317, 
showing  the  disposi- 
tion of  the  bundles, 
the  lettering  as  in 
"  317.-After  Nil 


—  </,  c,  — 


the  points 


from  which' the"' successive^ptiirs"1,?  gram  of  the  fibro-vascular  cylin- 

leave.RprtuB.-AfterOTgdl.  ^    Qf    ^^   ^^    (]?.         ^ 

projected  upon  a  series  of  transverse  and  vertical  lines  to 


442 


BOTANY. 


indicate  the  nodes  and  the  vertical  ranks  of  leaves)  the  sin- 
gle bundles  which  descend  from  the  leaves  are  shown  to  pass 
through  from  ten  to  twelve  internodes  before  uniting  with 


Fi<*.  319.— Diagram   showing  the  arrangement  of  the  fibro-vasculnr  bundles  im  22 
internodes  of  the  stem  of  Ibtris  atnara.-A.ttvT  Niigeli. 

other  bundles.  It  is  seen,  moreover,  that  there  an-  running 
through  the  stem  five  series  of  branching  bundles,  which  are 
not  quite  vertical,  but  slightly  spiral.  In  Fig.  320  is  shown 
the  appearance  of  an  actual  section  of  the  stem  taken  be- 


TISSUES  OF  ANGIOSPERMS. 


443 


Fig.  320.— Cross-section  of 


Uvee.i  the  fifth  and  sixth  leaves  of  the  preceding  figure.  The 
bundles  are  numbered  as  in  Fig.  319. 

542. — In  a  comparatively  small  number  of  instances  there 
are  fibro-vascular  bundles  in  the  stem  which  have  no  connec- 
tion with  the  leaves.  These  are  known  as  cauline  bundles. 

543. — In  the  Monocotyledons  and 
many  herbaceous  Dicotyledons,  the 
fibro-vascular  bundles  are  closed — that 
is,  there  is  no  zone  of  meristem  tissue 
left  between  the  xylem  and  phloem  after 
these  have  passed  over  into  permanent 
tissues.  There  is,  as  a  consequence,  a 
definite  period  of  groAvth  for  the  bun- 
dles, and  when  any  bundle  has  fully 
formed  all  its  tissues,  no  further  devel- 
opment can  take  place  in  it.  This  gen-  the  fifth  leaf. -After] 
erally  results  in  definitely  limiting  the  growth  of  the  inter- 
nodes,  and  in  consequence  such  plants  are  as  a  rule  short- 
lived. The  perennial  woody-stemmed  Dicotyledons,  and 
some  of  the  herbaceous  annuals,  possess  bundles  which  are 
open — that  is,  there  is  left  between  the  xylem  and  the  phloem 
a  zone  of  meristem  tissue  which 
continues  to  grow  long  after  the 
other  parts  of  the  bundle  have 
passed  over  into  permanent  tis- 
sues. Plants  with  such  bundles 
may  live  and  continue  to  grow  for 
an  indefinite  time. 

544. — A    cross-section    of    the 
stem  of  a  Palm  (Fig.  321)  shows 
it  to  be  composed  of  parenchyma- 
Fig.  3-21.  — Cross-section  of  the  tons  tissue  traversed  by  myriads 

stem  of  a  palm,    ec,  cortical  zone  ;  ,-111-1 

Iff,  the  softer  interior  portion  of  the  of  fibl'O-VaSCUlar  bundles,  which 
stem  :  lg',  the  harder  peripheral  .  , 

portion.— After  Duchartre.  descend  from  the  crown  of  leaves. 

Each  leaf  sends  down  from  its  broad  insertion  numerous 
bundles,  which,  in  a  vertical  section,  are  seen  first  to  pass  in 
toward  the  centre  of  the  stem,  and  then  to  curve  downward 
and  finally  outward.  The  centre  of  the  stem  is  thus  softer 
than  the  peripheral  portion,  as  in  the  latter  the  descending 


444 


SOT  ANY. 


bundles  are  more  numerous.  In  such  a  stem  it  is  evident 
that  there  can  be  no  considerable  increase  in  thickness  after 
it  is  once  formed,  and  we  consequently  find  that  palms 
take  a  longtime  for  the  formation  of  a  broad  bud  or  growing 
point  (punctumvegetationis),  and  afterward  push  up  a  cylin- 
drical stem  in  which  little  change  subsequently  takes  place. 

In  the  Dragon  trees 
(Draco?  na,  sp.)  and 
tome  other  Monoco- 
tyledons, there  is  a 
thick  layer  of  paren- 
chymatous  cortex  be- 
tween the  column  of 
fibro- vascular  bundles 
and  the  epidermis 
(Fig.  322,  r),  and  in 
the  deeper  layers  of 
this  a  persistent  meri- 
stem  tissue  is  found 
(Fig.  322,  .r).  In  this 
meristem  there  are 
formed  fibro-vascular 
bundles, which  lie  par- 
allel to  those  already 
formed,  and  in  this 
way  the  stem  slowly 
increases  in  thickness. 
545.— In  those  Di- 
cotyledons whose 
stems  increase  in 
thickness  there  always 

«,  meristem  zone  of  the   fundamental    system  in     i         i  i 

^yhich  new  bundles  and  tiseues  are  forming.-After    develops  SOO11    a   layer 

•  of     meristem    tissue, 

which  connects  the  cambium  layer  of  one  fibro-vascular 
bundle  with  that  of  the  other  (Fig.  323).  This  is  made 
easier  from  the  fact  that  in  most  (but  not  all)  Dicotyle- 
dons the  bundles  lie  at  nearly  the  same  depth  beneath  the 
epidermis  on  all  sides  of  the  stem,  thus  forming  a  cylinder, 
or  in  cross-section,  a  ring,  as  in  Fig.  323.  Both  the  t'ascicn- 


Fig.  322.—  Cioirs-section  of  f>tem  of  Draccenu.  e, 
epidermis ;  k,  cork  ;  r,  cortex  ;  6,  a  flbro  vascular 
bundle  bending  out  to  a  leaf  ;  »«,  parei  chyma  of  the 
fundamental  system  ;  g,  g,  flbro-vjiseular  bundles  ; 


TISSUES  OF  ANGIOSPEhMS. 


445 


Fig.  323.— Diagrams  of  dicotyledonous  stems  as  seen  in  cross-section.  R,  the  cor- 
tical, M,  the  medullary  portion  of  the  fundamental  system  ;  p,  the  phloem  ;  x,  the 
xylem  ;  b,  b,  b,  groups  of  bast  fibres ;  fc,  the  fascicular,  ic,  the  interfascicular  cam- 
bium.— After  Sachs. 


Fig.  324. — Cross-section  through  a  young  internode  of  Sambucus  nigra.    P,  P,  cor- 
tical parenchyma  ;  p,  p,  parenchyma  of  tin-  pith  :  between  r  —  randP—  P,  sieve  tis- 
iiid  above,  spiral  vessels  ;  <•  -  <•,  the  cumbiuni  zone,     x 


sue  ;  ff.  Qi  pitted  vessels ;  *•, 
«0.- After  De  Bary 


446 


BOTANY. 


lar  and  intcrfascicular  cambium  layers  are  composed  ot 
elongated  cells,  which  multiply  by  fission  in  a  tangential  di- 
rection, and  thus  give  rise  to  radiating  rows  of  cells  (Figs. 
334  and  335).  In  a  tangential  section  the  cambium  cells 
present  an  elongated  outline,  and  their  extremities  are 
usually  more  or  less  oblique  (Fig.  320).  From  these  cells 
there  develop  various  tissues.  Thus,  on  the  one  side,  the 
phloem  parenchyma,  sieve  and  fibrous  tissues  may  be  pro- 
duced by  more  or  less  great  modifications  (Fig.  327).  On 
the  other  side  (the  xylem  side)  new  ves- 
sels, fibres,  and  parenchyma  are  also  devel- 
oped (Fig.  328).  The  development  of 
these  tissues  begins  in  the  inner  and  outer 
layers  of  the  cambium,  and  advances  to- 
ward the  central  layers.  It  never  hap- 
pens, however,  that  all  the  cambium  lay- 
ers pass  over  into  permanent  tissues,  there 
always  remaining  one  or  a  few  meristem 
layers. 

546.— A  study  of  Figs.  326-328  will 
show  the  probable  mode  of  development  of 
the  permanent  tissues  from  the  meristem 
tissue  of  the  cambium.  It  is  evident  from 
a  comparison  of  Figs.  326  and  327  that 
the  phloem  parenchyma  is  produced  by 
the  formation  of  several  transverse  part  i- 

.  .  ,,  ,   .     .    *       . 

tions  in  each  cambium  cell,  and  it  is  prob- 
able  that  in  many  cases  there  is  a  direct 
conversion  of  cambium  cells  into  ,<icvc 
tubes.  That  the  cambium  cells  may  be 
converted  directly  into  trachei'des  is  evident  from  Fig.  326, 
and  also  Fig.  75  (p.  84).  In  Fig.  328  it  is  plain  that  the 
fibrous  tissue  (If)  and  trachei'des  (/)  have  the  same  origin, 
and  the  indications  are  that  even  the  large  pitted  vessels 
(fff/)  are  formed  from  cambium  cells  by  the  great  increase 
in  the  diameter  of  the  latter,  the  thickening  of  their  vertical 
walls,  and  the  partial  or  complete  absorption  of  their  trans- 
verse walls.  The  origin  of  the  xylem  parenchyma  from  cam- 


Fig.  325.— The  row  of 
cells  marked  x  —  as  in 


*  of  the  cambium 
cells.  X  600.  —  After 
De  Bary. 


TISSUES  OF  ANG10SPERMS.  447 

bium  cells  by  the  formation  of  transverse  partitions  is  very 
clear  in  this  figure. 

547. — In  the  trees  and  shrubs  of  cold  climates,  or  of 
those  in  which  there  is  one  annual  period  of  growth,  fol- 
lowed by  a  period  of  rest  or  the  cessation  of  growth,  the 


FIG.  327. 

Pig.  326.  A  tangential  section  of  the  cambium  region  of  Cytisus  Laburnum,  a,  6, 
c,  d,  cambium  eclN  enclosing  the  section  of  a  medullary  ray  ;  ft,  /i,  trache'ides  belong- 
ing to  the  xylem.  x  145.- After  De  Bary. 

Fig.  327.— Tangential  section  of  the  inner  phloem  region  of  the  same  stein  as  Fig. 
32G.  «,  «,*,  sieve  vessels  ;  m,  section  of  a  small  medullary  ray  ;  the  remaining  parts 
of  the  figure  are  phloem  parenchyma,  x  145.— After  De  Bary. 

processes  described  above  take  place  each  year,  giving  rise 
thus  to  an  annual  layer  of  xylem  (wood)  outside  of  the  pre- 
viously formed  xylem  cylinder,  and  an  annual  layer  of 
phloem  (bark)  inside  of  the  phloem  cylinder.  In  the  wood 
these  layers  are  generally  quite  well  marked,  and  in  cold 
climates  they  enable  us  to  determine  with  accuracy  the  age 


448 


BOTANY. 


of  trees  and  shrubs  (Fig.  329).  The  layers  of  the  bark  are 
rarely  well  marked,  and  they  generally  become  soon  obliter- 
ated by  irregular  corky  growths  in  the  substance  of  the  bark 


Kig.  328.— Tangential  section  of  the  stem  of  AUant.hus  fflinfltiloKvs.  through  i he 
secondary  xylem :  g,  g,  pitted  vest-els  ;  p,  p.  xylem  parenchyma  ;  at,  st.  medullary 
raysin  cross  section  ;  //,  fibrous  tissue  (Wood  cells) ;  t,  tracheides.  Highly  magnified. 
—After  Sachs. 

itself.  They  are,  moreover,  ruptured  by  the  increase  in  the 
diameter  of  the  woody  cylinder,  and  soon  decay  and  fall 
away.  It  thus  happens  that  while  the  annual  layers  of  the 
wood  are  constantly  increasing  in  number,  reaching  in  ex- 


TISSUES  OF  ANGI08PERM8.  449 

treme  cases  more  than  a  thousand,*  the  bark  rarely  shows 
more  than  a  few  distinct  layers,  and  its  thickness  is  generally 
very  much  less  than  that  of  the  former. 

From  what  has  been  said  it  is  seen  that  a  dicotyledonous  stem  several 
years  old  is  composed  of  a  series  of  larger  and  larger  continuous  woody 
shells  (Fig.  330,  1,  2,  3,  4,  5)  surrounded  by  a  corresponding  series  of 
bark  shells,  which  are  smaller  and  smaller  (Fig.  330,  5',  4'  3',  2',  10. 

548.— The  Medullary  Bays.  In  the  young  dicotyledonous 
stems  there  are  thick  masses  of  parenchyma,  which  connect 
the  cortical  with  the  medullary  (pith)  portion  of  the  funda- 
mental system  of  tissues  (Fig.  323).  However,  as  the  fibro- 
vascular  bundles  increase, 
these  masses  become  thin- 
ner, until  they  are  mere 
plates,  often  not  more  than 
one  or  two,  or  at  most  a 
few  cells  in  thickness  (Figs. 
326-7-8).  From  their  ap- 
pearance and  position  they 
have  long  borne  the  name 
of  Medullary  Eays.  In 
the  young  stem  their  cells 
may  be  parenchymatous,  '**• 

hnf  in  nlrlpr  mipu   thpv    nrr>  Fig.  329.- Cross-section  of  the  stem  of  an 

Olieb    tney    aiC  oak  ^(Quercu,  R<tbllr)  thirty-seven  years  old. 

frpfiiiontlv       <?plorpnpVivmi  m>  P^h  !  Iff-  heart-wood  ;  I'/',  sap-wood  ;  7-m, 

lequentiy                 icnyma-  mj,,\Illla;.y*ayH .  €C>  the  &g£  Much  reduced. 

tous.  Viewed  in  a  radial  -After  Duchanre. 
section  of  the  stem,  they  are  generally  seen  to  be  elongated 
in  the  direction  of  the  radius,  having  the  outlines  of  right- 
angled  quadrilaterals.  In  the  increase  of  the  diameter  of  the 
stem  there  is  always  an  increase  in  the  length  of  the  medul- 
lary rays,  both  in  their  bark  and  wood  portions  ;  and  when 
from  their  divergence  a  considerable  space  intervenes  between 
two  rays,  one  or  more  new  ones  arise  between  them  ;  thus 
while  there  may  be  no  more  than  four  or  five  rays  in  the 
young  plant,  it  may  when  old  have  hundreds  of  them  m  its 
circumference  (Fig.  329). 

What  has  been  said  of  the  tissues  of  the  Angiosperms  must  suffice  to 

*  In  t'ie  Lime  (Tilia  Europaa)  1076  and  1147,  and  in  the  Oak  (Qner- 
cris  Robur)  1080  and  1500,  according  to  De  Candolle. 


450 


BOTANY. 


mrf 


r 

J'2'3'4^'54331 


introduce  the  student  to  their 
study.  For  further  details, 
he  is  referred  to  De  Bary's 
admirable  treatise,  "  Ver- 
gleichende  Anatomie  der 
Vegetationsorgane  der  Phau- 
erogamen  und  Fame,"  in 
which  copious  references  are 
given.  The  publications  of 
JUT-  Russow  will  also  be  found  to 
> o  be  of  great  value  to  the  stu- 
|  £  dent. 

ll  549.— The  systematic 
1 1  arrangement  of  the  An- 
u^  giosperms  is  by  no  means 
fcjj  settled.  The  one  mostly 
K,r|  followed  in  England  and 
sr.S  this  country  is  a  modifi- 
S_.S  cation  of  De  Candolle's 
system  (A.D.  1813), 
which  was  itself  a  modi- 
fication of  Jussieu's  (A.D. 
1789),  which  in  turn  was 
based  upon  the  general 
system  proposed  by  Ray 
(A.D.  1703).  In  the 
"Genera  Plantarum," 
now  publishing  by  Ben- 
thani  and  Hooker,  and 
in  the  English  edition  of 
Lc  Maoutand  Decaisne's 
"  General  System  of  Bot- 
any," we  have  the  most 
recent  modifications  of 
the  Candollean  system. 
On  the  continent  of  Eu- 
rope other  systems  have 
been  used  more  or  less, 
and  it  is  probable  that 
gj;  among  these  are  to  be 
.Lh|  found  the  best  groupings 
*  &  of  Angiosperms  to  indi- 


ii 


2- 

A 
It 


MONOCOTYLEDONES. 


451 


cate  their  real  affinities.  Unfortunately  for  us,  however, 
none  of  our  systematic  manuals  follow  any  of  the  Continen- 
tal systems  ;  we  are  compelled,  tlieref ore,  to  use  for  the  pres- 
ent the  prevailing  form  of  the  Candollean  system.  In  this 
book  the  sequence  of  the  groups  is  the  reverse  of  that  in 
most  American  and  English  books,  in  order  to  bring  the  ar- 
rangement of  Angiosperrns  into  harmony  with  that  of  the 
rest  of  the  vegetable  kingdom. 

SUB-CLASS  I.  MONOCOTTLEDONES. 


550. 


(Endof/enm  of  De  Candolle.*) 
-In  these  plants  the  first 


Fig.  331.—  Longitudinal  section  of  the  seed 
of  Indian  corn  (Zea  Mais),  c,  adherent  wall 
of  the  ovary ;  n,  remains  of  the  style  \fg, 
base  of  the  ovary  ;  all  the  remainder  of  the 
figure  is  the  true  seed  ;  eg,  ew,  endosperm  ; 
to  —  «*,  cotyledon  of  embryo;  e,  its  epider- 
mis ;  k,  plumule  ;  w  (below),  the  main  root ; 
«,<,  theroot-shenth;  w  (above),  adventitious 
root  s  springing  fn>m  the  first  iuteruodo  of  the 
»teui.  x  0:— After  Sachs. 

has  its  broad  dorsal  surface  in  contact 


leaves  of  the  embryo  arc 
alternate,  hence  we  say 
that  they  have  one  cotyle- 
don. The  venation  of  the 
leaves  is  for  the  most  part 
such  that  the  veins  run 
more  or  less  parallel  to 
one  another,  and  when 
they  anastomose  enclose 
four-sided  areolae ;  rarely, 
however,  their  veins  are 
irregularly  distributed, 
and  they  anastomose  so  as 
to  form  an  irregular  net- 
work. 

The  germination  of  Monoco- 
tyledons may  be  illustrated  by 
a  couple  of  examples.  In  the 
seed  of  the  Indian  corn  the 
embryo  lies  partly  imbedded 
in  one  side  of  the  large  endo- 
sperm (Fig.  331).  The  first  leaf 
of  the  young  plant  (the  cotyle- 
don or  scutellum,  Fig.  331,  gc, 
with  the  endosperm  ;  anteriorly 


*  From  the  Greek  Ivtiov,  within,  and  yfi-etv,  to  bring  forth.  The 
name  was  given  under  the  false  impression  that  these  plants  were 
"  inside  growers,"  and  the  Dicotyledons  "  outside  growers." 


452 


BOTANY. 


Fig.  332.— Germination  of  Indian  corn.  /.,  77,  777, 
successive  stages.  A  and  B,  front  and  side  views  of 
a  separated  embryo.  In  the  figures,  w,  the  primary 
root ;  ws,  its  root-sheath  ;  w',  w",  adventitious  roots  ; 
w'",  lateral  roots  springing  from  the  main  root ;  f, 
part  of  seed  filled  with  endosperm  ;  ec,  cotyledon  ;  r, 
its  open  margins  ;  X%  the  plumule  ;  6,  V,  b",  leaves  of 
young  plant ;  /,  fragment  of  wall  of  ovary.  Natural 
Bize.-Af  ter  Sachs. 

Fig.  333.-Germinatioii  of  the  Date  (Phoenix  dacty- 
lifera).  I.,  transverse  section  of  seed  ;  c.  embryo  ;  «, 
endosperm.  77.,  777,  sections  of  germinating  seeds; 
c,  apex  of  cotyledon  developing  into  an  absorbing  or- 
gan ;  st,  stalk  of  cotyledon  :  *,  sheath  of  cotyledon  ; 
b',  b",  leaves ;  w,  root ;  w',  lateral  roots ;  h,  root-cap. 
71'.,  young  plant,  natural  size,  the  lettering  as  In  777. 
A.  section  of  IV.  at  a;  — w;  B,  section  at  x  —  //.  the 
lettering  as  in  777.  C,  section  at  *  —  «,  the  lettering  as 
in  777.-After  Sachs. 


GL  U MALES.  453 

it  is  curved  entirely  around  the  remainder  of  the  embryo.  Under  prop- 
er conditions  the  main  root  pushes  through  the  root  sheath  (ws,  Figs. 
331,  332).  The  plumule,  consisting  of  a  minute  stem  and  a  few  rudi- 
mentary leaves,  next  pushes  out  through  the  upper  end  of  the  curved 
cotyledon  (11. ,  Fig.  332).  The  cotyledon  remains  in  contact  with  the 
endosperm  and  absorbs  nourishment  from  it  for  the  sustenance  of  the 
growing  parts  Lateral  roots  soon  appear  upon  the  main  root,  and 
adventitious  ones  arise  from  the  first  internodes  of  the  stem  (w'",  w",  w', 
Fig.  332).  The  first  leaf  above  the  cotyledon  is  quite  small  (b),  and 
each  succeeding  one  becomes  larger  and  larger  until  the  full  size  is 
reached. 

In  the  Date  the  small  embryo  lies  imbedded  transversely  in  the  large 
endosperm.  In  germination  the  cotyledon  elongates  and  carries  the 
enclosed  root  and  plumule  outside  of  the  seed  (//.  and  III.,  Fig.  333). 
The  apex  of  the  cotyledon  (c)  expands  into  an  organ  through  which 
the  dissolving  endosperm  is  absorbed.  The  root  pushes  downward, 
and  soon  develops  lateral  roots  («/).  The  plumule  grows  upward,  es- 
caping from  the  enclosing  cotyledon,  as  shown  in  IV.,  Fig.  333.  The 
first  leaves  above  the  cotyledon  are  here,  as  in  the  Indian  corn,  much 
less  perfectly  developed  than  the  later  ones. 

551. — The  sub-class  Monocotylcdones  contains  about  fifty 
natural  orders  of  plants,  which  arc  grouped  into  fifteen  co- 
horts. Of  these  only  a  few  need  be  noticed. 

552.— Cohort  I.  Glumales.  Grass-like  plants  with  the 
flowers  in  the  axils  of  scales,  which  are  arranged  in  spike- 
lets  ;  the  stamens  are  from  one  to  three,  rarely  more ;  the 
single  ovary  contains  but  one  ovule,  and  these  at  maturity 
are  completely  coalesced,  forming  a  caryopsis. 

Order  Gramineee.— The  Grass  Family.  Herbaceous  or  rarely 
woody  plants,  with  round,  jointed,  and  mostly  hollow  stems,  bearing 
alternate  two-ranked  leaves  with  split  sheaths.  (Figs.  334-9.) 

This  very  natural  order  contains  about  4500  species,  which  are  dis- 
tributed in  all  climates.  In  the  tropics  they  are  large  and  almost  tree- 
like (Bamboo)  ;  in  the  temperate  climates  they  cover  the  ground  with 
a  close  mat,  while  in  the  colder  countries  they  grow  in  bunches.  Very 
many  of  the  species  are  valuable  on  account  of  their  starchy  seeds  or 
nutritious  herbage.  None  are  poisonous  (with  possibly  one  or  two  ex- 
ceptions). 

Triticum  vvlgare,  Wheat,  a  native  probably  of  Southwestern  Asia, 
has  been  under  cultivation  in  temperate  climates  for  several  thousand 
years.  Remains  of  wheat  grains  have  been  found  in  the  ruins  of  the 
lake  dwellings  in  Switzerland,  proving  that  it  was  cultivated  in  Europe 
in  prehistoric  times.  By  long  culture  it  has  formed  many  varieties; 


454 


BOTANY. 


some  of  these  are  hardy  (winter  wheats),   others  are  tender  (spring 
wheats) ;  some  are  awned,  others  awnless ;   in  some  the   grains  are 

FIGS.  334-9.— INFLORESCENCE  or  TUB  OAT. 


FIG.  339. 

Fig.  a34.— Spikelct. 

Fig.  335.— Spiketet  opened.     G.  glumes;  P,  palets ;  A,  awn  ;  F,  abortive  flower. 
Fig,  83»i.  —Flower  with  upper  palct. 
Fig!  33r.-Embryo. 
F'g.  338.- Section  of  grain. 
Fig.  339. -Diagram  of  spikelet.     Gl,  glumes  ;  B,  palets  ;  A,  abortive  flower. 

dark  in  color  (red  wheats),  in  others  they  are  light  colored  (white 
wheats).  Fabre's  experiments  about  a  quarter  of  a  century  ago  appear 
to  indicate  that  wheat  was  originally  derived  from  a  wild  grass  called 


OLU  MALES. 


455 


JEgttops  ovata.  From  it,  in  the  course  of  from  ten  to  twelve  years,  he 
succeeded  in  producing  the  form  known  as  cultivated  wheat.  (See 
Gardener's  Chroniclf,  July,  1852.) 

Secale  cereale,  Rye,  is  probably  a  native  of  Southeastern  Europe  and 
Southwestern  Asia.  It  has  been  cultivated  for  ages  and  is  still  much 
grown  in  temperate  climates. 

Hordeum  vulgare,  Barley.  A  native  probably  of  the  same  region  as 
Rye  ;  has  also  been  long  under  cultivation.  One  or  two  other  species 
are  also  grown. 

Avena  saliva,  the  Oat,  was  formerly  much  used  as  food  for  man. 
especially  in  cool  climates,  where  it  succeeds  best.  It  is  now  less  used. 
Its  native  country  is  not  certainly  known,  but  it  was  probably  northern 
Europe  or  Asia. 

Oryza  sativa,  Rice,  has  been  long  under  culture  in  Southeastern 
Asia,  of  which  country  it  was  probably  a  native.  It  is  now  cultivated 
also  in  Egypt,  Italy,  Brazil,  and  the  Southern 
United  States.  It  furnishes  food  to  more  human 
beings  than  any  other  single  plant. 

Zea  Mais,  Maize  or  Indian  Corn,  a  native  of 
the  warmer  parts  of  the  New  World,  was  culti- 
vated by  the  aborigines  of  both  North  and  South. 
America  before  the  advent  of  Europeans.  It  is 
one  of  the  most  valuable  of  the  cereals,  and  is 
now  cultivated  almost  all  over  the  world.  Of  its 
numberless  varieties  the  larger  are  grown  in  the 
hotter,  and  the  smaller  in  the  cooler  climates. 

The  more  important  forage  grasses  are  the  fol-  J&JtS^SSS^  of 
lowing :  Rice. 

Phleum  pratense,  Timothy  or  Herd's  Grass,  a  native  of  Europe  is  val- 
uable on  rich  soils. 

Agrostu  vulgaris,  Red-top,  a  native  of  Europe,  grows  well  on  moist 
soils. 

Ductylis  glomerata,  Orchard  Grass,  a  native  of  Europe,  is  valuable 
because  of  its  growing  well  in  the  shade,  and  so  furnishing  hay  and 
pasture  in  orchards  and  woodlands. 

Poa  pratensis,  Kentucky  Blue  Grass,  a  native  of  the  Eastern  United 
States  and  of  Europe,  is  in  the  latitude  of  Kentucky  the  best  of  all  our 
pasture  grasses.  In  drier  regions  it  is  small  and  harsh. 

Muhlenbergia  glomerata  and  M.  Mexicana  constitute  the  "  Fine 
Slough  Grass  "  of  the  Mississippi  valley  prairies.  They  furnish  val- 
uable hay. 

Several  species  furnish  sugar  : 

Saccharum  officinarum.  Sugar  Cane,  a  native  of  the  warmer  parts  of 
Asia,  is  a  large  plant  somewhat  resembling  Indian  corn  in  size  and  ap- 
pearance. From  its  sweet  juice  most  of  the  sugar  and  molasses  of  com- 


456 


BOTANY. 


inerce  are  made.     It  is  cultivated  extensively  in  the  Southern  United 
States,  Cuba,  Brazil,  and,  in  fact,  in  all  warm  countries  of  the  world. 

FIGS.  341-4. — ILLUSTRATIONS  OF  CABEX. 


FIG.  342.  FIG.  343.  FIG.  344. 

Fig.  341.— Underground  stem,  sending  up  leafy  and  flowering  stems. 
Fig.  342.-Male  flbwer.    Magnified. 
Fig.  343.— Female  flower.    Magnified. 
Fig.  344.-Section  of  seed.    Magnified. 

It  is  a  curious  fact  that  while  the  annual  production  of  cane  supar  in 
the  world    is    now  about  4,000,000,000    pounds,  yet    five    hundred 


LILT  A  LES  457 

years  ago  it  was  but  little  known  to  our  European  ancestors,  and  even 
a  century  and  a  half  ago  it  was  one  of  the  luxuries.  (Simmonds.) 

Sorghum  vulgare,  Chinese  Sugar  Cane,  a  native  of  India,  has  within  a 
few  years  been  brought  into  cultivation  in  the  United  States  for  its 
sweet  juice,  from  which  molasses  and  sugar  are  made.  One  variety  of 
this  species  is  the  Broom  Corn,  used  in  the  manufacture  of  brooms. 

Several  species  of  Bamboo  (Bambusa,  sp.)  growing  in  India  become  so 
large  as  to  supply  materials  for  building  the  houses  of  the  natives. 

B.  arundinacea  sometimes  attains  the  height  of  30  metres  (100  ft.). 
Its  uses  are  almost  innumerable. 

Order  Cyperaceee. — The  Sedge  Family.  Herbaceous  plants,  with 
three-angled  solid  stems,  bearing  alternate  three-ranked  leaves,  with 
entire  sheaths.  (Figs.  341-4.) 

There  are  about  two  thousand  species  of  sedges,  which  are  distrib- 
uted throughout  the  world.  They  grow  in  tufts,  never  forming  a  con- 
tinuous mat,  and  generally  prefer  wet  localities.  They  are  of  little 
value  to  man,  and  their  stems  contain  so  little  nutritious  matter  that 
they  are  eaten  only  to  a  limited  extent  by  animals. 

Cyperus  esculentus,  the  Clmfa,  a  native  of  the  Mediterranean  region, 
is  somewhat  cultivated  for  its  small,  sweet-tasting  tubers. 

Cyperus  tea-tilis  is  used  in  India  for  making  ropes  and  mats  ;  in  Egypt 
other  species  are  used  for  the  same  purpose. 

Papyrus  antiquorum,  Papyrus,  is  a  tall  growing  plant  with  stems  2-3 
cm.  (1  inch)  in  diameter.  It  is  a  native  of  Egypt  and  the  adjacent 
countries,  and  from  it  the  inhabitants  anciently  made  paper  by  slicing 
its  cellular  pith,  and  afterward  hammering  and  smoothing  it. 

553.  Cohort  II.  Restiales. — This  includes  three  orders  of 
mostly  tropical  plants  bearing  glumaceous  flowers. 

Orders  Restiacese,  Eriocaulonacese,  and  Flagellariew. 

554.  Cohort   III.    Commelynales. — Plants  with  a  hexa- 
merous  perianth,  in  two  whorls,  the  inner  colored  and  petal- 
oid. 

Orders  Mayaceee,  Xyridacese,  and  Commelynaceee. 

The  latter  contains  the  well-known  Spiderwort    Tradescantia,  sp.). 

555.  Cohort  IV.    Pontederales. — Marsh   plants   with   a 
gamophyllous  petaloid  perianth. 

Orders  Philydrese,  Pontederiacese,  and  Rapateee. 

556.  Cohort  V.    Liliales. — Plants   with   a   hexamerous 
(rarely  tetramerous)  perianth,  the  parts  united  or  free,  and 
usually  petaloid. 

Order  Juncacese. — The  Rushes.     Natives  of  temperate  and  cold 


458 


BOTANY. 


climates.     The  leaves  and  stems  are  woven  into  matting  and  chair 
bottoms,  and  the  pith  is  used  for  the  wicks  of  candles  (rush-lights). 

Order  LiliaceaB.— The  Lily  Family.  Perennial,  mostly  herbaceous 
plants,  with  entire  leaves,  and  generally  showy  flowers.  The  species, 
of  which  there  are  about  two  thousand,  are  distributed  in  all  climates. 
Some  of  these  are  valuable  as  food,  others  furnish  useful  medicines, 
while  many  are  among  our  finest  ornamental  plants. 

The  more  important  food  plants  are  the  following  : 

Attium  Cepa,  the  Onion,  a  native  probably  of  the  Mediterranean  re- 
gion, is  grown  throughout  the  world. 

Alllum  Porrum,    the   Leek,   A.  satwum,   Garlic,   A.    ascalonicum, 

FIGS.  345-8.— ILLUSTRATIONS  or  FRITILLARIA. 


FIG.  345. 
Fig  345.— Section  of  flower. 
Fig.  34«.— Flower  diagram. 
Fig.  347.— Section  of  ovary. 
Fig.  348.-Ovule. 

Shallot,  and  a  few  other  species,  all  natives  of  the  Old  World,  are  con- 
siderably  used. 

Asparagus  officinali*,  Asparagus,  is  a  native  of  the  Atlantic  and 
Mediterranean  coasts  of  Europe,  and  of  the  sandy  plains  of  Central  and 
Western  Asia.  It  has  been  cultivated  in  England  for  upwards  of  two 
thousand  years,  but  it  is  an  interesting  fact  that  in  all  that  time  it  has 
exhibited  very  little  variation. 

Among  the  medicinal  plants  may  be  mentioned 

Aloe  vulgaris,  of  the  Mediterranean  region,  and  other  species  in 


LILIALES. 


459 


Southern  and  Eastern  Africa,  the  inspissated  juice  of  whose  leaves  con- 
stitutes tin;  drug  Aloes. 

Smilax  officinalis,  of  South  America,  and  other  species,  furnish  Sarsa- 
parilla  root. 


Fi<j.  349.— Underground  parts  of  Colchicum  autumnale  at  the  time  of  flowering. 
A,  front  view  :  jfc,  old  conn  ;  *',  s",  scales  surrounding  flower  stalk.  B,  section  show- 
ing new  stem,  h',  with  rudimentary  leaves.  I',  I"  ;  the  very  long  tubular  flowers,  6,  ft7, 
spring  from  near  the  summit  of  the  new  stem,  h'.  The  following  spring  h'  will  elon- 
gate aud  carry  the  fruit,  and  leaves  V,  I",  above  ground  ;  the  lower  part  of  hf  will  en- 
large into  a  conn  like  *',  while  at  k"  a  new  plant  will  form  as  a  lateral  bud.— After 


Scilla  maritima  ;  the  sliced  bulb  of  this  Mediterranean  sand  plant  ia 
the  drug  Squill. 

Veratrum,  album,  the  White  Hellebore  of  the  mountains  of  Central 


±60  BOTANY. 

Europe,  and  V.  viride,  Green  Hellebore  of  the  Eastern  United  States, 
are  poisonous  emetics.     The  rhizome  is  officinal. 
Ornamental  plants : 

Asphodelus  lutem  is  the  Asphodel  of  Southern  Europe. 
Agapanthus  umbellatux,  the  Love  Flower  of  the  Cape  of  Good  Hope, 
is  a  beautiful  green-house  plant,  bearing  pale  blue  flowers. 

Colchicum  autumnale,  the  "  Meadow  Saffron  "  or  "  Autumn  Crocus  " 
of  Europe,  is  curious  for  its  producing  leaves  in  the  spring,  and  then, 
long  after  these  have  died  dowu,  in  the  autumn  sending  up  one  or  two 
long-tubed  pale  flowers,  which  soon  wither  away  ;  the  following  spring, 
by  the  lengthening  of  the  underground  stein,  the  seed-pod  is  carried 
up,  along  with  the  green  leaves  (Fig.  349).  The  corms  of  this  plant 
were  formerly  in  some  repute  as  medicines. 

ConvaUaiia  majalis,  the  Lily  of  the  Valley,  is  a  native  of  woodlands 
and  shady  places  in  England,  Europe,  and  Siberia. 

Drficcsna  Draco,  the  Dragon  Tree  of  Western  Africa  and  the  adja- 
cent islands,  is  cultivated  as  a  curiosity  in  green-houses.  A  tree  of 
this  species  on  the  island  of  Teneriffe  was,  at  the  time  of  its  destruc- 
tion by  a  hurricane  in  1867,  upwards  of  20  metres  (70  ft.)  high,  and  5 
metres  (16  ft.)  in  diameter,  and  from  its  known  slow  growth  it  must 
have  been  many  hundreds,  possibly  some  thousands,  of  years  old. 

FritiUaria,  imperiilis,  the  Crown  Imperial,  a  native  of  the  south  of 
Europe  and  Western  Asia,  is  a  showy  plant. 

fhinkia,  sp. ,  and  HemerocaMis,  sp.,  the  Day  Lilies,  the  former  from 
China  and  Japan,  the  latter  from  Southern  Europe,  and  Hyacinthm 
orienlalis,  the  Hyacinth  of  Asia  Minor,  are  in  common  cultivation. 

Lilium — many  species.     The  True  Lilies.     Aside   from  our  native 
species,  L.   Phitadelphicum,  L.  Canadense,  and  L.  superbum,  which 
deserve  cultivation,  the  following  are  commonly  found  in  gardens  : 
L.  bulbiferum,  the  Orange  Lily,  from  Southern  Europe  :  flowers 

orange. 

L.  tigrinum,  the  Tiger  Lily,  from  China  ;  flowers  orange-red. 
L.  Pomponium,  the  Turban  Lily,  from  Europe  ;  flowers  red. 
L.  Chcdcedonicum,  the  Red  Lily,  from  Asia  Minor;  flowers  red. 
L.  Martagon,  the  Turk's  Cap  Lily,  from  Europe  ;  flowers  flesh- 

colored. 

L.  speciosum,  the  Showy  Lily,  from  Japan  ;  flowers  rose-colored. 
L.  auratum,  the  Golden  Lily,  from  Japan  ;   flowers   white   and 

golden. 

L.  candidum.  the  White  Lily,  from  Asia  Minor;  flowers  white. 
L.  Japonicum,  the  Japan  Lily,  from  Japan  ;  flowers  white. 
L.   longiflorum,   the  Long  flowered   Lily,   from    Japan ;    flowers 

white. 

Myrsipfiyttumasparagoides,  a  delicate  climber  from  the  Cape  of  Good 
Hope,  is  grown  in  windows  and  conservatories  under  the  name  of 
Smilax. 


ARALE8.  461 

Ornithogalum  umbettatum,  the  Star  of  Bethlehem,  is  a  native  of  Cen 
tral  Europe. 

Polianthes  tuberosa,  the  Tuberose,  a  native  probably  of  the  East 
Indies,  bears  a  tall  spike  of  fragrant  white  flowers.  It  is  sometimes 
placed  in  the  order  Amaryllidacese. 

Ruscus  aculeatus,  the  Butcher's  Broom  of  England  and  Southern 
Europe,  a  curious  shrub,  with  flat  leaf-like  branches,  is  rarely  cultivated 
with  us. 

Tritoma  uvaria,  of  the  Cape  of  Good  Hope,  bears  a  tall  spike  of  red 
flowers,  and  hence  receives  in  cultivation  the  name  of  the  "  Red-Hot 
Poker  Plant." 

Tulipa  Oesneriana,the  Tulip,  is  a  native  of  tbe  Levant.  It  was 
brought  into  Europe  about  three  hundred  years  ago,  and  originally 
bore  yellow  flowers,  but  under  long  culture  it  has  developed  number- 
less varieties.  To  the  Dutch  we  owe  much  of  the  improvement  in  this 
flower  ;  in  the  first  half  of  the  seventeenth  century  throughout  Holland 
so  much  attention  was  given  to  its  culture,  and  such  high  prices  paid 
for  single  bulbs  of  the  finer  varieties,  that  a  speculative  mania  (known 
as  the  "  tulipomania")  arose,  resembling  the  wildest  of  modern  grain 
or  stock  manias. 

Yucca,  of  several  species,  known  by  the  name  of  Adam's  Needle, 
Spanish  Bayonet,  Bear  Grass,  etc.,  is  a  genus  of  fine  ornamental 
plants,  natives  of  the  warmer  parts  of  America.  The  strong  fibres  are 
sometimes  made  into  cordage.  The  roots  contain  saponin,  and  are 
used  by  the  Mexicans  instead  of  soap  for  washing. 

Xanthorrhaia  includes  the  curious  Grass  Gum  Trees  of  Australia. 

557.— Cohort  VT.  Arales.— A  group  of  dissimilar  plants, 
some  being  large  trees,  and  others  microscopic  floating  herbs. 

Order  Lemnaceee.— The  Duckweeds.  These  smallest  of  Phanero- 
gams consist  of  floating  disks  (thalli),  with  no  distinction  of  leaf  and 
stem,  bearing  one  or  several  roots  beneath  (in  Woljfia,  however,  no 
roots).  They  are  parenchymatous  throughout,  or  with  only  rudiment- 
ary vascular  tissues.  Their  flower-clusters  are  sunken  into  pits  in  the 
top  or  edge  of  the  disks,  and  consist  of  one  or  two  stamens  and  a  single 
pistil,  representing  as  many  reduced  flowers.  There  are  about  twenty 
species,  widely  distributed  throughout  the  northern  hemisphere.  We 
have  eight  or  ten  species  in  the  United  States.  (Figs.  350-2.) 

Order  Aroideee.— The  Arum  Family.  Herbs  often  large  and  palm- 
like  in  appearance,  with  large  leaves  having  reticulated  venation.  In- 
florescence generally  surrounded  by  a  spathe.  Of  the  Aroids  there  are 
about  1000  species,  distributed  mostly  in  tropical  countries,  where  they 
sometimes  attain  a  height  of  several  metres  (6-12  feet) ;  in  temperate 
climates  they  are  much  smaller.  They  possess  an  acrid  juice,  which 
may  be  poisonous. 


462 


BOTANY. 


Some  of  the  species  have  been  used  in  medicine,  among  which  are 
the  Indian  Turnip  (Arismma),  and  Sweet  Flag  (Acorus). 

Calocasia  antiquorum,  a  large  plant  of  the  tropics,  is  there  grown  for 
its  fleshy  farinaceous  corm.  It  is  grown  with  us  for  its  fine  foliage. 

Richardia  Afiicana,  the  so-called  Calla-lily,  or  Ethiopian  Lily,  a  na- 
tive of  the  Cape  of  Good  Hope,  is  a  common  green-house  plant. 

Symplocarpus  fmtidus,  the  Skunk-cabbage  of  the  Northern  United 
States,  is  remarkable  for  the  mephitic  odor  of  its  bruised  leaves. 

AmorphopTiallus  Titanwn,  an  Aroid  discovered  in  1878  by  Beccari  in 


FIGS.  350-2. — ILLUSTRATIONS  OF  LEMNA. 


Fig.  350.— Two  plants  of  L.  minor.    Magnified. 
Fig.  351.— Three  flowers  in  a  spathe. 
Fig.  352.— Section  of  pistil. 

Sumatra,  has  an  enormous  spathe,  1.7  metres  (6  feet)  in  depth,  and  83 
cm.  (2f  feet)  in  diameter. 

Order  Typhacese,  represented  by  the  two  genera  Typha  and  Spar- 
ganium. 

Order  Pandanaceae. — Mostly  tropical  plants,  some  of  them  of  a 
tree-like  aspect. 

Pandanus  includes  the  Screw  Pines  of  the  East  Indies,  so  called  from 
the  spiral  arrangement  of  their  clustered  leaves. 

Carludovica  palmata,  a  Central  American  plant,  with  palmate  radical 
leaves  borne  on  petioles  three  metres  (8-10  feet)  long,  is  important  as 
furnishing  the  material  from  which  the  famous  Panama  hats  are 
made. 

558.— Cohort  VII.  Palmales. —Shrubs  or  trees  with  di- 
vided (rarely  simple)  leaves.  Flowers  in  a  spadix. 


PALMALUS. 


463 


Orders  Nipaceae  and  Phytelephasieee,  both  of  the  tropics.  In 
the  latter,  Phytelephas  macrocarpa,  of  Central  America,  ia  remarkable 
for  the  ivory-like  endosperm  in  its  large  seeds  ;  hence  its  name  of 
Ivory  Nut. 

Order  Palmaceee.— The  Palm  Family.  Trees,  shrubs,  or  woody 
climbers  ;  natives  almost  exclusively  of  the  torrid  zone,  or  the  adjacent 

FIGS.  .353-6.— ILLUSTRATIONS  OP  PALMACE.B. 


FIG.  356. 


FIG.  355. 
docarp  ;  c,  testa  ;  d,  endosperm  ; 


Fig.  353. — Fruit  of  Cocoa-nut,    a,  exocarp  ; 
f,  embryo  ;  /,  milk  cavity. 
Fig.  354. — Cocoa-nut  seen  from  below. 
Fisj.  355.— Vertical  section  of  a  Date,  showing  seed  inside. 
Fig.  356.  -  Seed  of  Date  in  cross-section,  showing  embryo. 

hotter  portions  of  the  temperate  zones,  being  rarely  found  beyond  40° 
North  and  35°  South  latitude.  The  arborescent  species  are  among  tlie 
most  striking  and  majestic  of  plants;  their  long  cylindrical  stems  fro 
quently  rise  to  the  height  of  thirty  metres  (100  feet),  bearing  at  their 
summits  spreading  crowns  of  large  leaves, and  drooping  clusters  of  fruit. 
The  whole  number  of  known  species  ia  not  far  from  one  thousand. 
The  economic  value  of  the  Palms  is  very  great ;  in  fact  it  may  be<jues- 


464  BOTANY. 

tioned  whether  any  other  order  of  plants  (the  G  raises  possibly  excepted) 
approaches  them  in  the  importance  of  the  products  they  furnish.  Every 
species  appears  to  be  useful,  and  the  uses  of  some  of  the  species  may 
be  reckoned  by  hundreds.  In  some  countries  every  want  of  man  is 
supplied  by  one  or  another  of  the  palms. 

I.  Tribe  Cocoinece.—Atalea  Juniftra  is  a  Brazilian  species  of 
stout-growing  trees,  whose  fibrous  leaves  are  used  in  making  ropes, 
mats,  and  coarse  brooms.    The  nuts,  known  as  Coquilla  nuts,  are  seven 
to  eight  cm.  (3  inches)  long,  very  hard,  and  are  used  for  making  door- 
handles, bell-pulls,  etc. 

Cows  nucifera,  the  Cocoa-nut  Palm,  is  a  native  of  the  coasts  of  tropi- 
cal Africa,  India,  Malay,  and  islands  of  the  Indian  and  Pacific  Oceans. 
It  is  now,  however,  cultivated  throughout  the  tropics.  The  tree  varies 
in  height  from  fifteen  to  thirty  metres  (50  to  100  feet),  and  bears  long 
pinnate  leaves.  The  nuts,  which  are  borne  in  clusters  of  seven  to  ten 
or  more,  are  the  well-known  cocoa  nuts  of  commerce.  As  a  new  cluster 
is  pushed  out  every  month,  the  annual  yield  of  a  single  tree  may  be 
from  100  to  150  or  more  nuts,  and  this  may  continue  for  forty  years.  In 
some  parts  of  India  and  other  countries,  the  white  albumen  of  the  nut 
forms  nearly  the  entire  food  of  the  natives,  and  the  milk  serves  them 
for  drink.  In  this  country  great  quantities  are  used  as  a  delicacy  and 
for  culinary  purposes. 

In  cocoa-nut  countries  the  uses  of  the  root,  stern,  leaves,  and  fruit  are 
said  to  be  as  numerous  as  the  days  in  the  year,  sufficing  for  all  the  wants 
of  the  inhabitants.  The  root  is  used  as  a  masticatory  ;  the  stem  is  used 
for  the  most  diverse  purposes,  while  the  hard  case  of  the  base  is  used 
for  making  drums,  and  in  the  construction  of  huts,  the  tender  termi- 
nal bud  is  highly  prized  as  an  article  of  food.  The  juice  of  the 
flower-stems  is  rich  in  sugar,  and  this,  by  fermentation,  produces  an  ex- 
cellent wine,  and  by  distillation  yields  a  spirit  called  arrack.  From  the 
sheaths  and  leaves  the  natives  construct  roofs,  fences,  baskets,  buckets, 
ropes,  mats,  brooms,  and  numerous  other  articles.  The  fibre  from  the. 
leaves  and  sheaths  is  imported  into  this  country  and  made  into  "  coir" 
ropes,  floor-matting,  brushes,  and  brooms,  and  used  also  for  stuffing 
cushions.  Even  the  hard  shell  is  of  use  in  the  manufacture  of  cuj  a 
and  ornaments. 

Eltris  guineenm,  of  West  Africa,  produces  annually  large  quantities 
of  pulpy  fruits,  each  containing  a  hard  nut.  From  these  palm  oil  is 
obtained,  which  is  used  in  Europe  and  the  United  States  for  making 
candles,  for  the  manufacture  of  soap,  and  also  to  some  extent  for  lubri- 
cating purposes. 

II.  Tribe  Coryphinece.—Copernica  ccrifera,  the  Wax  Palm  of 
Brazil,  attains  the  height  of  twelve  metres  (40  feet),  with  a  diameter  of 
stem  of  thirty  cm.  (1  foot).     The  hard  wood  takes  a  fine  polish,  and  is 
used  for  veneering.     The  young  leaves  are  coated  with  a  waxy  secre- 
tion which  is  used  in  England  for  making  candles. 


PALM  ALES.  465 

Phanix  dactylifera,  the  Date  Palm,  is  a  native  of  Northern  Africa 
and  Western  Asia,  now  naturalized  in  the  south  of  Europe.  The  tree 
is  dioscious,  and  grows  to  the  height  of  ten  to  twelve  metres  (40-50 
feet),  bearing  a  crown  of  leaves,  each  leaf  being  four  to  six  metres  (15- 
20  feet)  long.  The  fruit  is  produced  in  large  bunches,  containing  from 
twenty  to  thirty  dates.  Dates  constitute  a  large  portion  of  the  food  of 
the  Arabs  of  the  African  and  Arabian  deserts.  They  are  largely  im- 
ported into  the  United  States.  They  are  prepared  by  gathering  before 
they  are  quite  ripe,  and  then  drying  in  the  sun. 

The  cultivation  of  the  date  palm  has  for  ages  been  an  object  of  first 
importance  in  Arabia  and  Northern  Africa.  The  trees  are  hereditary, 
and  are  sold  as  estates,  constituting  the  chief  wealth  of  the  inhabi- 
tants. 

Sabal  Palmetto  the  Cabbage  Palmetto,  S.  serrulata,  the  Saw  Palmetto, 
S.  Adansonii,  the  Dwarf  Palmetto,  and  Ghamcerops  Uystrix,  the  Blue 
Palmetto,  all  of  the  southeastern  United  States,  and  Washingtonia  fil- 
ifera,  of  California  and  Arizona,  are  our  principal  native  palms. 

III.  Tribe  Borassinece.—Borassus  flabelliformis,  the  Palmyra 
Palm,  is  a  native  of  nearly  all  Southern  Asia.     It  has  large  fan-shaped 
leaves,  anda  cylindrical  stem  rising  to  the  height  of  fifteen  to  thirty  me- 
tres (50  100  feet).     Wine,  or  toddy,  and  sugar  are  made  from  the  juice  ; 
the  young  sprouts  of  the  flowering  branches  a.re  used  for  food  in  the 
same  manner  as  asparagus.    From  the  stem  is  obtained  Palmyra  wood. 

HypliCKne  thebaicn,  the  Doum  or  Gingerbread  Palm,  is  a  branching 
species  of  the  upper  Nile  region.  It  produces  fruits  of  the  size  of  an 
apple  and  with  the  flavor  of  gingerbread.  A  resin  derived  from  this 
tree  is  known  as  Egyptian  Bdellium. 

Lodoicea  sechellarum,  the  Double  Cocoa-nut  of  the  Seychelle  Islands 
in  the  Indian  Ocean,  is  a  giant  among  the  palms.  It  attains  the  height 
of  thirty  metres  (100  feet),  its  stem  being  forty-five  to  sixty  cm.  (1£  to  2 
feet)  in  diameter.  It  produces  large  oblong  nuts,  which  have  the  ap- 
pearance of  being  double,  and  which  weigh  from  thirty  to  forty  pounds. 
They  are  borne  in  bunches  of  nine  or  ten  in  number,  so  that  a  whole 
bunch  will  often  weigh  400  pounds.  It  takes  ten  years  to  ripen  the 
fruit,  the  albumen  of  which  is  similar  to  that  of  the  common  cocoa-nut, 
but  it  is  too  hard  and  horny  to  serve  as  food.  The  leaves  are  made  into 
hats,  baskets,  etc.  The  demand  for  the  leaves  for  these  uses  has  become 
PO  great  that  the  trees  are  cut  down  in  order  to  obtain  them,  and  as  no 
care  is  taken  to  form  new  plantations,  it  is  feared  that  this  palm  will 
eventually  become  extinct. 

IV.  Ti*ibe  Calamecp.— Calamus  Rotang  and  several  other  spe- 
cies include  the    Rattan  or  Cane  Palms   of   India  and   the  Malayan 
Islands.     They  have   slender   reed-like  stems  which  grow  to  a  great 
length,  often  from  sixty  to  one  hundred  or  more  metres  (200-300  feet), 
and  are  imported  into  Europe  and  the  United  States  for  making  chair- 
bottoms,  umbrella-ribs,  etc, 


466  BOTANY. 

Calamus  Draco,  of  the  same  region  as  the  preceding,  yields  a  reddish 
resinous  substance  known  as  Dragon's  Blood,  and  which  is  a  secretion 
coating  the  surface  of  the  small  fruits.  Dragon's  blood  is  used  for  col- 
oring varnishes  and  for  staining  horn. 

Sagus  lewis  and  8.  Rumphii,  Sago  Palms,  are  trees  nine  to  fifteen 
metres  (30-50  feet)  nigh,  natives  of  Siam,  the  Indian  Archipelago  and 
other  islands  of  the  East.  The  sago  is  obtained  by  splitting  the  trunks 
and  extracting  the  soft  white  pith  ;  this  is  thrown  into  tanks  of  water, 
in  which  it  is  repeatedly  washed  and  strained  until  a  pure  pulpy  paste 
is  obtained.  In  this  state,  in  order  to  preserve  it,  the  natives  keep  it 
under  water,  and  it  forms  a  large  proportion  of  their  food.  For  expor- 
tation it  is  dried  and  granulated  through  sieves.  A  tree  fifteen  years 
of  age  yields  from  six  to  eight  hundred  pounds  of  this  nutritious 
material. 

V.  Tribe  Arecinece.—Areca  Caterhu,  the  Betel  Palm  of  Cochin 
China  and  the  Malayan  peninsula  and  islands,  produces  a  fruit  of  the 
size  of  a  hen's  egg,  which  is  the  famous  Betel  Nut  or  Pinang  of  the  far 
East.  The  nut  is  cut  into  pieces  and  rolled  up  with  lime,  gambier,  etc., 
in  a  leaf  of  the  betel  pepper,  and  chewed  as  tobacco  is  in  this  country. 

Caryota  urens,  of  India,  is  one  of  the  wine  or  "  Toddy"  palms.  It 
grows  to  the  height  of  fifteen  to  eighteen  metres  (50-60  feet),  and  has  a 
large  crown  of  compound  winged  leaves.  It  is  said  that  this  tree  will 
yield  one  hundred  pints  of  toddy  in  twenty-four  hours. 

Ceroxylon  andicola,  the  Wax  Palm  of  the  mountains  of  New  Granada, 
is  a  tall  tree,  bearing  large  pinnate  leaves  five  to  six  metres  (15-20  feet) 
long.  It  is  found  on  the  mountain  sides  nearly  to  the  snow  line.  The 
trunk  is  coated  with  a  resinous  wax,  which  is  scraped  off  by  the  natives 
and  used  for  making  candles. 

Chammdorea  of  several  species,  climbing  palms  of  New  Granada  are 
interesting  on  account  of  their  stems  being  used  in  forming  suspension 
bridges. 

Saguerus  saccharifer  of  the  Malayan  Archipelago  is  a  valuable  Sago 
Palm.  It  is  twelve  to  fifteen  metres  (40-50 feet)  high,  and  bears  enor- 
mous pinnate  leaves  ;  a  tree  grown  in  the  Kew  Gardens  bore  leaves 
twelve  metres  (40  feet)  in  length.  Sugar  is  also  obtained  from  the 
juice  which  flows  from  the  wounded  spadix. 

559.  Cohort  VIII.  Potamales. — Mostly  herbaceous  wa- 
ter plants,  with  all  of  the  parts  of  the  flower  distinct ;  the 
embryo  large,  and  endosperm  wanting. 

Order  Naiadaceee.— The  Pond-weeds. 

Order  Alisxnaceae.— The  Water  Plantain  Family.  This  order  is 
interesting  from  the  fact  of  its  evident  relationship  to  the  Ranales 
(Cohort  36)  among  Dicotyledons,  as  long  ago  suggested  by  Adanson, 
and  insisted  upon  by  Lindley.  (Figs,  357-9.) 


NARGI8SALES.  46? 

Alisma  and  Sagittaria  are  two  common  genera. 

560.  Cohort  IX.    Triurales,  with  one  small  and  little 
known  order. 

Order  Triurideae. — Delicate,  almost  colorless  herbs  of  the  tropics. 

561.  Cohort  X.  Dioscorales. — Climbing  herbs  or  under- 
shrubs,  bearing  reticulately  veined  leaves. 

Order  Dioscoreaceae. — The  Yam  Family.  Several  species  of  Dios- 
eorea  produce  edible  tubers. 

D.  sativa,  D.  aculeata,  and  other  species  of  India  are  extensively 
grown  there  and  in  the  West  Indies  as  potatoes  are  grown  in  cooler 
climates. 

D.  Batatas  and  D.  Japonica  are  known  as  Chinese  Yams. 

Testudinaria  elephantipcs,  of  the  Cape  of  Good  Hope,  is  a  curious 

FIGS.  357-9.— ILLUSTRATIONS  op  ALISMA  PLANTAGO. 


FIG.  357 


Fig.  357.— Flower  cnt  vertically.    Magnified. 

Fig.  358.-Seed.    Magnified. 

Fig.  359.— Section  of  seed.    Magnified. 

green-house  plant,  having  a  large,  woody,  above-ground  corm-stem, 
from  which  spring  every  year  slender  twining  stems. 

562.  Cohort  XI.  Narcissales. — Plants  with  narrow,  often 
equitant  leaves,  having  parallel  venation  ;  seeds  containing 
endosperm. 

Order  Haemodoraceae. — The  Blood- wort  Family. 

Order  AmaryllidaceaB.— The  Amaryllis  Family.  Distinguished 
from  the  oext  order  by  having  six  stamens,  and  leaves  which  are  not 
equitant.  The  four  hundred  species  are  herbs  of  temperate  and  trop- 
ical climates  ;  many  possess  a  narcotic  and  poisonous  principle. 

Agave  Americana,  the  Century  Plant  of  Mexico,  is  now  much  grown 
in  conservatories,  and  is  said  to  be  naturalized  in  Southern  Europe.  In 
California  and  its  native  country  it  blooms  at  the  age  of  from  ten  to 


408  BOTANY. 

fifteen  years,  but  in  cool  climates  it  requires  from  thirty  to  seventy  or 
more.  The  mature  plant  has  a  cluster  of  thick,  sharp-pointed  radical 
leaves,  each  about  2  metres  (6  ft.)  long,  from  the  centre  of  which  it 
sends  up  a  flowering  stem  10-15  cm.  (4-6  in.)  thick,  and  5-6  metres 
(16-20  ft.)  high,  bearing  hundreds  of  yellow  flowers.  The  Mexicans 
cut  out  the  central  bud  just  before  the  lengthening  of  the  flowering 
stem,  and  from  the  juice,  which  flows  out  in  great  abundance,  obtain 
by  fermentation  the  drink  called  "  Pulque,"  or  by  distillation  the  more 
generally  used  "  Mescal."  The  subterranean  stems  possess  a  detergent 
principle,  and  under  the  name  of  "  Amole  "  are  much  used  by  the 
Mexicans  in  washing.  The  strong  fibres  in  the  leaves  are  used  for 
cordage. 

Hcemantlivs  toxicaria,  of  South  Africa,  has  a  poisonous  bulb,  which 
is  used  by  the  Hottentots  for  poisoning  their  arrows. 
Many  species  are  grown  for  the  beauty  of  their  flowers  ;  among  these 
may  be  mentioned : 

Amaryllis,  of  many  species,  mostly  from  South 
Africa  and  South  America. 

Galanthus  nivalis,  the  Snowdrop,  of  Europe. 
Leurojum  vcrwtm,  the  Snow-flake,  of  Europe. 
Narcissus,  of    many  species ;   this   includes  the 
Daffodil,  Jonquil,    Polyanthus,  etc.,  all   natives  of 
Europe. 

Order  Iridaceae.— The  Iris  Family.  The  sta- 
ceae.— After  Sachs.  niens  are  only  three  (by  the  abortion  of  an  inner 
whorl,  Fig.  360),  and  the  leaves  are  equitant.  The  order  contains  five 
hundTed  species,  which  are  mainly  found  in  the  south  temperate  clim- 
ates, a  smaller  number  occurring  in  north  temperate  regions.  They 
contain  a  purgative  principle,  which  has  been  used  in  medicine. 

Crocus  vernus  and  other  species  are  commonly  grown  for  their  early 
spring  flowers  ;  the  dried  stigmas  of  C.  sutivus  constitute  the  drug  Cro- 
cus or  Saffron  used  in  medicine  and  also  in  dyeing. 

Gladiolus  psittacinus  and  other  species,  from  the  Cape  of  Good  Hope, 
are  deservedly  popular  as  ornamental  plants. 

Iris  Oermanica,  of  Europe,  and  many  other  Old  World  species,  are 
common  in  gardens. 

Our  native  /.  versicolor ,  I.  cristata,  and  others,  are  also  worthy  of 
culture. 

563.  Cohort  XII.   Taccades.— This  includes  two  small 
tropical  orders  of  herbaceous  plants. 

Orders  Taccaceee  and  Burmanniaceee. 

564.  Cohort  XIII.  Orchidales. — Herbs  with  a   hexamor- 
ous  (rarely  trimerous)   zygomorphic  perianth  ;  the  .stamens 
and  style  more  or  less  confluent  int:>  a  common  column,  and 


ORCHIDALE8. 


4G9 


the  minute  seeds  containing  a  rudimentary  embryo  and  no 
endosperm. 

Order  Apostasiacese,  a  small  order  of  East  Indian  plants,  which  are 
interesting  because  of  their 
evident  relationship  to  the 
Orchids,  from  which  they 
differ  in  having  the  style 
partially  free  from  the  sta- 
mens. 

Order  Orchidaceee.  — 
The  Orchids.  Terrestrial 
or  epiphytic  plants,  whose 
stamens  and  style  are  com- 
pletely united  into  a  com- 
mon column  or  gynoste- 
mium.  The  three  thousand 
species  are  found  in  "  all 
climates  and  in  all  situa- 
tions but  maritime  and 
aquatic."  (Hooker.) 

This  order  has  long  been 
highly  esteemed  for  the 
many  curiously  shaped  and 
colored  flowers  it  affords, 
and  many  hundreds  of  its 
species  are  to  be  found  in 
cultivation  in  conservato- 
ries. They  are  interesting 
also  from  the  fact  that  none 
of  them  are,  unaided,  capa- 
ble of  fertilizing  their 
ovules,  and  appear  in  every 
case  to  be  dependent  upon 
insects  for  the  transjxm  of 
the  pollen  and  its  deposition 
upon  the  stigma. 

This  great  order  is  usu- 
ally divided  into  seven 
tribes,  as  under. 


Fig.  361.— Orchis  maculata.     A,  a  symmetrical 
vertical  section  of  a  flower  bud.   B,  transverse  sec- 


™    .,        _        _  .  tion  of  the  bud.     6',  transverse  section  of  ovary. 

Tribe    I.      Cypripe-    D.  mature  flower,  with  one  sepal  removed;   x, 
<f<eo>f  with  two  pollinifer- 
ous      stamens      containing    mass ; 
granular  pollen  (Fig.  362).      SWjF^ 

In  this  the  genus  Cypri-  minodes.— After  Sachs. 
pedium,  which  contains  our  native  LadyVSHppers,is  the  most  important. 
Some  of  the  species,  notably  C.  upec'abile  and  C.  acnule,  are  greatly  ad 
mired  in  cultivation. 


470 


BOTANY. 


Tribe  II.  Neottiece,  with  a  single  dorsal  anther,  containing 
two  or  four  soft  pollen  masses  attached  to  a  viscid  disc.  Our  principal 
genus  is  Spiranthes. 

Tribe  III.  Aretftusece,  with  a  single  terminal  anther,  contain- 
ing two  or  four  powdery  pollen  masses. 

Our  native  Arethv&a  and  Cal->pOffon  are  fine  representatives  of  this 
tribe.  The  Vanilla  plant  (Vanilla  plauifolia,  and  other  species)  of 
tropical  America,  a  climbing  epiphyte,  produces  fleshy  capsules  12  to 
25  cm.  (5—10  in.)  long,  which  are  highly  aromatic,  and  much  used  in 
the  manufacture  of  confections,  beverages,  medicines,  etc.  When  first 
introduced  into  the  East  Indies,  where  it  is  now  much  grown,  it  failed  to 
perfect  fruit ;  artificial  p  llination  hav- 
ing been  resorted  to,  however,  the  dif- 
culty  at  once  disappeared.  (Fig.  363.) 
Tribe  IV.  Ophrydece,  with  a 
single  anterior  anther,  containing  two 
stalked  pollen  masses,  each  attached  to 
a  viscid  disc  (Fig.  361). 

Our  pretty  little  Orchis  spectabilis, 
and  many  species  of  Hdbenana,  are 
our  principal  representatives  of  this 
tribe.  From  the  tubers  of  Orchis  mas- 
cula  and  other  European  and  Asiatic 
species,  the  starchy-mucilaginous  and 
highly  nutritious  substance  "  Salep," 
is  obtained. 

Tribe  V.  Vandece,  with  a  single 
terminal  or  dorsal  anther,  containing 
Fig.  362  —  Sexual  organs  of  the    waxy  pollen  masses  attached  to  a  vis- 
flower  of  Ct,pri]>e(iium  calceolus,  the    cjd  disc 
perianth,  p,  removed.    A,  side  view. 
B,  back  view.    C,  front  view.  /,  the        We  have  no  native  representatives 

imstenTium*-^  a^taiii^""^"^^^  °*  *^8  tri°e-  Many  of  the  tropical 
stamen  or  etaniinode  ;  »,'  stigma.—  species  are  of  wonderful  forms;  indeed, 
After  Sachs.  ag  Mr  Darwm  says  of  them,  tlu-y  arr 

"  the  most  remarkable  of  all  Orchids."  In  some  genera  they  assume 
the  most  curious  forms,  resembling  insects  of  various  kinds,  birds,  etc., 
etc.  In  Catasetum  saccatum,  a  diclinous  South  American  species, 
when  certain  sensitive  parts  of  the  column  of  the  male  flower  are 
touched  by  an  insect,  the  pollen  masses  are  by  a  peculiar  contrivance 
thrown  out  forcibly  in  such  a  direction  as  to  strike  the  insect,  to 
which  it  adheres  by  a  viscid  disc,  and  is  thus  carried  to  and  brought  in 
contact  with  the  stigma  of  the  female  flower. 

Tribe  VI.  Epidt  ii(/rea>,  with  a  single  terminal  anther,  contain- 
ing stalked,  waxy  pollen  masses,  these  not  attached  to  a  viscid  disc.  To 
this  tribe  belong  in  the  United  States  Tipularia,  Bletia,  ami  l^ii'lm- 
drum,  the  latter  an  epiphyte,  occurring  only  in  the  Southern  States. 


AMO  MALES. 


471 


Of  the  exotics,  Ccdogyne,  Lalia,  Cattleya,  etc.,  are  to  be  seen  in  conserva- 
tories. 

Tribe  VII.  Malaxidece,  with  a  single  dor- 
sal, terminal,  or  anterior  anther,  which  contains  four 
stalkless,  waxy  pollen  masses,  not  provided  with  a 
viscid  disc. 

Calypso,  Liparis,  Corallarhiztt,  and  other  genera 
occur  in  the  United  States  ;  the  last  named  appears 
to  be  parasitic.  Among  the  many  exotics  may  be 
mentioned  Bulbophyllum,  Dertdrobium,  Malaxis, 
etc. 

565.  Cohort  XTV.  Amomales.  —  Herbs 
(some  almost  arbores- 
cent) with  hexamerous 
and  mostly  zygomor- 
phic  perianth  ;  sta- 
mens six,  generally 
from  one  to  five  only 
polliniferous. 

Order    Bromeliacese. 

—  The  Pine-apple  Family. 

Distinguished     from    the 

next  by  the  regular  flow- 

ers   and   six    perfect   sta- 

mens.   About  two  hundred 

species  of  almost  entirely 

tropical   plants   constitute 

this  order.    But  one  genus 

(^Misrepresented 

in    the    Southern    United 

States  ;  of  the  eight  or  ten 

native  species,  the  Long  Moss  (T.  usneoides)  of  the 

Southern  Atlantic  coast  is  the  best  known.     It  is 

used  in  upholstery  and  in  the  manufacture  of  mat- 

tresses. 

Ananassa  sativa,  the  Pine-apple,  supposed  to  be 

a  native  of  Brazil,  is  now  cultivated  throughout  the 

world.     In  cool  climates  it  is  grown  in  hot-houses, 

and  it  is  said  that  these  are  much  better  than  those 

grown  out  of  doors  in  warm  climates.     The  fleshy 

fruits  are  aggregated  into  solid  cone-like  masses  (Fig. 
Fig.  3&3.—  Ripened    864),  the  well-known  Pine-apples  of  commerce. 
op!'7anSwingthe       Order  Scitamineee.—  The  Banana  Family,  with 
6eeds-  zygomorphic  perianth,  and  one  to  five,  very  rarely 

^ix,  perfect  stamens.     Three  sub-orders  are  well  marked. 


awa    sativa)  terminated 
a  tuft  of  leave8' 


472 


BOTANY. 


Sub-Order  Musce,  with  five  polliniferous  stamens  (rarely  six). 

The  genus  Musa  contains  several  exceedingly  valuable  plants.  M. 
sapientum,  the  Banana,  and  M.  paradisiaca,  the  Plantain,  of  the  trop- 
ics everywhere,  are  large  herbs,  3-5  metres  (10-15  ft.)  high,  with  the 
sheathing  petioles  of  their  large  leaves  forming  a  tree-like  stem. 
Their  well-known  fruits  constitute  almost  the  sole  article  of  food  for 
millions  of  people  in  the  tropics,  and  are  also  largely  exported  to  all 
countries.  It  has  been  calculated  that  from  twenty-five  to  sixty-six 
tons  of  bananas  can  be  grown  upon  an  acre  of  ground,  supplying  more 
nourishment  to  man  than  is  afforded  by  any  other  plant.  They  are 
considerably  grown  in  hot-houses,  both  as  ornaments  and  for  their 


Fig.  365.— Part  of  a  flowering  plant  of  the  Banana,  showing  the  unfolding  flower- 
bud  and  the  young  fruits. 

fruits.  From  their  leaves  and  petioles  a  good  fibre  is  obtained,  and 
from  the  allied  M.  textilis  of  the  East  Indies  is  obtained  "  Manilla 
Hemp,"  so  much  used  in  the  manufacture  of  various  textile  fabrics. 

Strelitzia  Regince,  of  the  Cape  of  Good  Hope,  is  a  common  conserva- 
tory plant. 

Sub-Order  Zingiberce,  with  one  polliniferous  stamen,  bearing 
a  two-celled  anther.  Several  of  these  tropical  plants  are  important. 

Curcuma  longa,  of  the  East  Indies  and  tropical  Pacific  islands,  has 
a  yellow  colored  rhizome,  which  constitutes  the  well  known  dye, 
"Turmeric." 

Zingiber  officinale,  the  Ginger  Plant,  probably  a  native  of  India,  is 
now  grown  in  most  tropical  countries  for  its  aromatic  rhizomes,  which 


DKOTTLEDONE8.  473 

when  dried  and  powdered  constitute  the  ginger  of  commerce.     That 
from  the  West  Indies,  called  Jamaica  Ginger,  is  considered  the  best. 

Sub-Order  Canute,  with  one  polliniferous  stamen,  bearing  a 
one-celled  anther.  Aside  from  Camia,  with  its  many  ornamental  spe- 
cies now  common  in  gardens,  one  other  plant  deserves  mention,  viz.  : 

Maranta  arundinacea,  a  native  of  tropical  America,  now  grown  ex- 
tensively for  its  fleshy  rhizomes,  from  which  a  starch  known  as  "Arrow- 
root "  is  obtained. 

566.  Cohort  XV.  Hydrales. — Small  aquatic  plants,  with 
a  hexamerous  regular  perianth,  and  stamens  three,  six,  nine, 
or  twelve. 

Order  Hydrocharideee. — This  contains  the  Eel  Grass,  Vcdlisneria 
spiralis,  and  Water  Weed,  Anacharis  Ganaden»is, 
common   in  our  ponds  ;  the  latter  is  naturalized  in 
England,  where  it  chokes  up  streams. 

Fossil  Monocotyledons. — The  earliest  Mono- 
cotyledon, so  far  as  known  at  present,  was  a  Tri- 
assic  species  of  Yuccites,  doubtfully  referred  to  the 
Liliaceae.  In  the  Jurassic  the  Gramineae,  Cyper- 
aceae,  Liliaceae,  Naiadaceae,  and  Pandanaceae  were  Fig  see.— Diazram 
represented  by  a  few  species.  In  the  Cretaceous  the  of  ihe  flower  of  C'an- 
T. .  *  ,  na,  showing  theoreti- 

Caunae,    Dioscoreaceai,   and   PalUMCeee   appeared.       cai  structure.  —  After 

A  species  of  the  last-named  order  has  been  discov-  Sacl18- 
ered  in  the  Cretaceous  of  Western  Kansas.  In  the  Tertiary  most  of  the 
modern  orders  of  Monocotyledons  were  represented  (however,  no  orders 
of  Cohorts  II.,  III.,  and  XIII.  have  yet  been  found).  Fifteen  species 
of  palms  have  been  described  from  the  Tertiary  of  the  Great  Plains 
and  the  Rocky  Mountain  region,*  extending  as  far  north  as  northern 
Dakota  and  Vancouver's  Island.  Their  remains  are  also  abundant  in 
the  Tertiary  of  Mississippi. 

SUB-CLASS    DICOTYLEDONES. 

(Exogence  of  De  Candolle.f) 

567. — In  the  plants  of  this  sub-class  the  first  leaves  of  the 
embryo  are  two  and  opposite,  hence  they  are  said  to  have 
two  cotyledons.  The  venation  of  the  leaves  is  for  the  most 

*  "  Contributions  to  the  Fossil  Flora  of  the  Western  Territories. 
Part  II.  The  Tertiary  Flora,"  by  Leo  Lesquereux.  Washington,  1878. 

f  From  the  Greek  l£u,  outside,  and  yeveiv,  to  bring  forth.  The 
name  is  no  longer  a  proper  one,  as  we  now  know  that  these  plants 
are  not,  strictly  speaking,  "  outside  growers ; "  on  the  contrary,  they 
increase  in  thickness  by  the  growth  of  an  internal  meristem  layer. 


474 


BOTANY. 


part  such  that  the  veins  rarely  are  parallel  to  each  other,  and 
in  their  anastomosing  they  form  an  irregular  net-work. 

The  germination  of  Dicotyledons  may  be  illustrated  by  a  couple  of 
examples.  In  the  seed  of  the  Windsor  Bean  (Fig.  367)  the  embryo 
entirely  fills  up  the  seed-cavity,  the  endosperm  having  all  been  ab- 

FIGS.  367-8. — GKRMINATION  OP  DICOTYLEDONS. 


FIG.  368. 


Fig.  367. —  Vleiafaba.  .4, seed  with  one  cotyledon  removed;  c,  remaining  cotyle- 
don ;  kn,  the  plumule  :  w,  the  radicle  ;  «,  seed-coat.  S,  germinating  seed  ;  «,  seed- 
coat,  partly  torn  away  at  1;  n,  the  hilum ;  at,  petiole  of  one  of  the  cotyledons;  *, 
curved  epicotyledonary  stem  ;  Ar,  short  hypocotyledormry  stem ;  h.  main  root ;  ws, 
its  apex  ;  kn,  hud  in  the  axil  of  one  of  the  cotyledons. — After  Sachs. 

Fig.  3BS.—Jticinug  commnnis.  I.,  lon-ritudinul  section  of  the  ripe  need.  II.,  ger- 
minating seed  with  the  cotyledons  still  inside  of  the  seed-coat  (shown  more  distinct- 
ly in  A  and  B).  «,  seed-coat ;  e,  endosperm  ;  c,  cotyledon  ;  Ac,  hypocotyledonary 
stem  ;  w,  primary  root ;  w1,  branches  of  root ;  a,  caruncle,  a  peculiar  appendage  to 
the  seeds  of  Kuphmbiocece.— After  Sachs. 


sorbed.  The  thick  cotyledons  lie  face  to  face,  and  are  attached  below 
to  the  small  stem  of  the  embryo  plant.  The  stem  extends  upward  a 
short  distance  between  the  cotyledons,  bearing  a  few  rudimentary 
leaves  and  itself  ending  in  a  punctum  vegetationis  (Fig.  369,  *«),  the 
whole  constituting  the  plumule.  The  downward  prolongation  of  the 
stem  (commonly  but  erroneously  called  the  radicle,  for  it  is  not  a  little 


DICOTYLEDON ES. 


475 


root)  ends  in  a  very  short  root,  which  is  continuous  with  the  stem.* 
Under  the  proper  conditions  of  heat  and  moisture,  the  root  elongates 
and  pushes  out  through  the  micro- 
pyle  of  the  seed-coat ;  at  the  same 
time,  the  stalks  of  the  cotyledons 
elongate  and  thus  bring  the  plumule 
outside  of  the  seed-coat,  the  cotyle- 
dons alone  remaining.  During  the 
first  few  days  of  its  growth  the 
young  plant  is  nourished  by  the 
starch  in  the  cotyledons,  which  in 
this  species  remain  during  the  whole 
process  of  germination  beneath  the 
ground  enclosed  in  the  seed-coat.  In 
the  common  Field  Bean  (Phascolus) 
the  germination  is  the  same,  except- 
ing that  the  hypocotyledonary  stem 
elongates,  and  brings  the  cotyledons 
which  have  slipped  out  of  the  seed- 
coat  above  the  ground. 

The  seed  of  Eicinus  (the  Castor 
Oil  Plant)  contains  a  large  embryo 
surrounded  by  a  thin  layer  of  endo- 
sperm (Fig.  368,  /).  In  its  germina- 
tion the  root  and  hypocotyledonary 
stem  elongate,  and  thus  bring  the 
seed-coat  with  the  contained  coty- 
ledons above  the  ground  (Fig.  368, 
//.).  The  cotyledons  remain  within 
the  seed-coat  until  they  have  absorb- 
ed all  of  the  endosperm  ;  when  this 
is  accomplished  the  empty  seed-coat 
falls  away,  and  the  freed  cotyledons 
expand  and  assume  to  some  extent 
the  function  of  ordinary  foliage 
leaves. 

The  venation  of  the  leaves  of  Di- 
cotyledons is  easily  studied  by  mac- 
erating  them   so  as  to  remove  the    cotyledons.    ss.'apex  of"  the  stem  ,  „„, 
*  ,     ,,.       ,  Of  tne  root ;  ct.  BWGuttlff  near  insertion 

parenchyma  (mesophyll),  leaving  of  cotyledons  •  i,  the  Irst  Interaode" 
only  the  fibro-vascular  bundles,  fi  the  Petioles  of  the  first  foliage 
wvii  xi "  i  leaves  ;  «.  «,  /,  procambium  of  the 

While  there  is  as  a  rule  a  general    flbro- vascular  bandies  •  ho  hypocoty- 

likeness  between  them,  there  is  yet  SS^I^^r^SlSSS 
an  almost  infinite  diversity  in  the  Sachs. 

*  In  some  old  books,  and  even  a  few  recent  ones,  a  structure  called 
the  collar  or  collwn  is  spoken  of.     Dr.  Gray  very  properly  defines  it  as 


476  BOTANY, 

details.     The  general  disposition  of  the  smaller  veins  is  well  illustrated 
by  Fig.  369a.* 

568. — The  sub-class  Dicotyledones  is  composed  of  thirty- 
six  cohorts,  containing  in  all  from  150  to  200  natural  orders. 
For  convenience,  the  cohorts  are  separated  into  three  artifi- 
cial groups — the  Apetalae,  Gamopetalae,  and  Choripetalae 
(Polypetalae) — an  arrangement  which  does  violence  to  nature, 
separating  widely  many  orders  which  are  evidently  closely 
related  to  each  other. 

I.  APETALuE.  Plants  whose  flowers  generally  have  but 
a  single  floral  envelope  (calyx), 
this  even,  in  some  cases,  wanting. 
569.  Cohort  1 .  —  Santalales. 
Herbs,  shrubs,  or  trees,  mostly 
parasitic,  with  inferior  ovary, 
generally  naked  ovules — i.e.,  no 
integuments — and  seeds  usually 
containing  endosperm. 

Order  Balanophoreee.  —  Fleshy 
leafless  parasites,  mostly  of  the  trop- 
ics. One  species,  Cynomorium  cocdn- 
eum,  of  the  Mediterranean  region,  is 
sometimes  eaten. 
Order  Santalaceee. — Leafy  herbs, 

Fig.  369a.— Fragment  of  a  learof  a    shrubs,  or  trees,  mostly  parasitic,  num- 

Dicor.yledon  (Psorcdea  bituminosa).  ,  nf.n  .  •,.  •, 

showing    reticulated    venation.    r\    bering   about    200    species,  which  are 

margiuBof  leaf,     x  40.— After  De   distributed   in  temperate  and  tropical 

regions. 

Comandra  umbellate,  a  perennial  herb,  is  our  most  common  repre- 
sentative of  the  order. 

Sanlalum  album,  the  Sandalwood  Tree  of  South  Asia,  attains  a  height 
of  seven  to  eight  metres  (25  feet).  Its  dark  red  wood  is  used  in  cabinet- 
making,  and  for  burning  incense  in  Buddhist  temples.  Other  species 
from  the  Pacific  islands  also  furnish  sandalwood. 

The  Quandang  Nut  of  Australia  is  the  edible  fruit  of  a  small  tree, 
Fnsanus  ncuminatus. 

"  the  name  of  an  imaginary  something  intermediate  between  primary 
stem  and  root." 

*  The  student  who  wishes  to  study  this  subject  fully  should  consult 
the  papers  of  Dr.  Ettingshausen,  published  in  Denkschriften  and 
Mitzungsberichte  Wien.  Kais.  Akad.  Wissen.  They  are  excellently  il- 
lustrated with  many  "  nature  printed"  plates. 


QUERN  ALES.  477 

Order  Loranthaceae.  The  Mistletoe  Family.  Evergreen  shrubs, 
parasitic  upon  other  Dicotyledons.  About  450  species  are  known  ; 
these  are  mostly  tropical. 

Viscum  album,  the  Mistletoe  of  England,  Europe,  and  Northern 
Asia,  grows  abundantly  upon  the  apple  and  many  other  trees,  rarely, 
however,  upon  the  oak.  The  viscid  fruits  are  used  in  making  bird- 
lime, and  its  twigs  and  branches  are  much  used  in  Christmas  decora- 
tions in  England.  It  was  held  sacred  by  the  Druids,  who  made  use  of 
it  in  their  religious  ceremonies. 

Phoradendron  flavescens,  the  American  Mistletoe  of  the  Southern 
United  States,  is  well  known.  On  the  Pacific  coast,  a  variety  of  this 
species  is  common  on  the  oaks. 

Six  species  of  Arceuthobium,  small  brown  branching  parasites  on 
Conifers,  are  known  in  the  United  States.  A.  pusillum  occurs  in  the 
Northern  States. 

570.  Cohort  II.— Quernales.  Trees  and  shrubs,  not  at 
all  parasitic,  with  diclinous  flowers,  mostly  in  catkins,  infe- 
rior ovaries,  and  seeds  destitute  of  endosperm. 

Order  Cupulifereee.  The  Oak  Family.  Trees  or  shrubs  with 
simple  leaves  ;  fruits  (nuts),  one-celled,  one-seeded,  one  to  three  en- 
closed in  an  involucre.  This  valuable  order  contains  about  300  species, 
which  are  distributed  mainly  in  the  Northern  Hemisphere  ;  in  the  South- 
ern Hemisphere  they  occur  in  Chili,  New  Zealand,  and  the  mountains 
of  South  Australia.  Most  of  the  species  are  astringent,  which  is  due 
to  the  tannin  they  contain. 

The  order  is  of  great  economic  importance  on  account  of  its  valuable 
wood,  which  is  used  not  only  as  a  fuel,  but  still  more  in  the  manufac- 
ture of  implements  and  utensils,  and  in  the  construction  of  houses, 
ships,  etc.  It  is  divided  into  two  sub-orders,  which  are  sometimes  re- 
garded as  orders. 

Sub- Order  Corylece.     Shrubs  and  small  trees. 

Carpinus  Americana,  the  Blue  Beech,  or  Hornbeam,  is  a  small  native 
tree  with  white,  fine-grained,  hard  wood.  As  the  European  C.  betulus 
is  used  in  turnery,  doubtless  our  species  might  be  also. 

Corylus  Avettana,  the  Filbert,  is  a  shrub  growing  wild  in  Europe  and 
Western  and  Northern  Asia,  and  now  cultivated  in  Europe  and  the 
United  States.  It  is  grown  principally  for  its  edible  nuts,  although  the 
straight  rod-like  branches  are  largely  used  in  making  hoops,  crates  for 
merchandise,  etc.  White  Filberts,  Red  Filberts,  Cob-nuts,  and  Bar- 
celona-nuts are  some  of  the  cultivated  varieties.  C.  Americana,  the 
common  wild  Hazel-nut  of  the  Eastern  United  States,  is  much  like  the 
preceding,  but  smaller  in  size  of  shrub  and  nuts.  Its  nuts  are  gath- 
ered and  eaten,  and  are  occasionally  found  in  the  markets. 

Ostrya  Virginica,  the  Ironwood  of  the  Eastern  United  States,  is  a 
small  tree  having  a  hard,  fine-grained  wood,  which  is  valuable  for  fuel. 


478 


BOTANY. 


Although  capable  of  many  uses  in  the  arts,  it  has  been,  to  a  great  ex- 
tent, neglected.  The  trunks  of  the  young  trees  are  much  used  for 
levers  in  saw-mills  and  log-yards,  hence  one  of  its  popular  names, 
Lever-wood. 

Sub-Order  Quercinece.    Mostly  large  trees. 

Costarica  vesca,  the  so-called  Spanish  Chestnut,  is  a  native  of  Asia 

FIGS.  370-74.— ILLUSTRATIONS  OF  QUKRCUS  ROBUB. 


FIG.  370.  Fia.  374. 

Fig  370. -Male  and  female  branches,  with  a  ripe  fruit  at  the  side. 
Fig.  371.— Male  flower.    Magnified. 
Fig.  372.— Female  flower.    Magnified. 
Fig.  373. — Female  flower,  in  vertical  section.    Magnified. 
Fig.  374. -Vertical  section  of  fruit. 

Minor  and  the  region  eastward  to  the  Himalayas  It  is  found  in  Cen- 
tral and  Southeastern  Europe,  but  it  was  probably  introduced  from  the 
East  2000  or  more  years  ago.  It  furnishes  a  valuable  coarse-grained 
timber,  and  its  fruits  are  the  "Spanish  Chestnuts  "of  the  marketH. 


QUERN  ALES.  479 

Several  varieties  occur  in  North  Africa,  Japan,  and  North  America.  0. 
vesca,  var.  Americana,  our  native  Chestnut,  of  the  Eastern  United 
States,  is  a  large  tree,  with  smaller  and  sweeter  nuts  than  the  Old 
World  variety.  Its  wood,  which  is  light,  coarse-grained  and  easily 
worked,  is  highly  prized  for  making  doors,  cases,  certain  kinds  of  fur- 
niture, etc. 

Fagus  syhatica,  the  Beech  of  Europe  and  Western  Asia,  supplies  a 
hard  wood  much  used  in  chair-making,  turnery,  and  in  the  manufac- 
ture of  wooden  shoes.  Purple  Beech,  often  cultivated  as  a  curiosity, 
is  a  variety  of  this  species. 

F.  ferruginea,  the  common  Beech  of  the  Eastern  United  States,  is  a 
large  spreading  tree  ;  its  wood  is  reddish  in  color,  and  of  great  hard- 
ness when  dry,  and  is  used  in  making  carpenters'  tools,  and  for  other 
purposes.  Its  nuts,  known  as  Beech-nuts  or  Beecli-Mast,  are  nutritious, 
and,  where  abundant,  are  used  for  fattening  swine. 

In  Southern  South  America,  New  Zealand  and  Australia ,  there  are 
six  or  seven  evergreen  species  of  this  genus. 

The  genus  Quercus  includes  the  Oaks,  in  all  about  250  species,  which 
are  widely  distributed  in  the  Northern  Hemisphere  ;  none  occur  be- 
yond the  equator.  De  Candolle  (Prodromus,  Vol.  XVI.)  divides  the 
genus  into  six  sections,  four  of  which  are  exclusively  Southeastern' 
Asiatic. 

SECTION  I. — The  Scaly-Cupped  Oaks.  These  include  the  common 
oaks  of  Europe  and  America.  They  are  again  subdivided  into  two  sub- 
sections—viz., the  White  Oaks  and  the  Black  Oaks. 

(a)  White  Oaks. 

Quercus  Robur,  the  British  Oak,  of  England  and  the  Continent  of 
Europe.  It  is  a  stately  tree,  supplying  a  most  valuable  timber  for  all 
kinds  of  constructive  purposes,  in  naval,  civil,  and  military  engineering. 
It  is  considered  to  be  superior  to  all  other  kinds  of  oak  for  its  timber. 
The  bark  contains  tannin,  and  is  much  used  in  tanning.  (Figs.  370-4.) 

Q.  Lusitanica,  var.  infectoi-ia,  of  the  Levant,  produces  the  Nutgalls 
of  commerce  ;  these  are  morbid  growths  on  the  petioles  or  midribs  of 
the  leaves,  resulting  from  punctures  made  by  an  Hymenopterous  insect 
of  the  genus  Cynips.  Their  value  lies  in  the  tannin  they  contain. 

Q.  alba,  the  White  Oak  of  the  Eastern  United  States,  stands  next  to 
Q.  Robur  in  the  value  of  its  timber,  which  is  used  in  this  country  as 
British  Oak  is  in  Europe. 

Q.  virena,  the  Live  Oak  of  the  Southeastern  United  States,  and  ex- 
tending westward  to  Texas,  is  a  large  tree,  twelve  to  twenty  metres 
(40-60  feet)  high,  with  spreading  branches,  bearing  small  entire  ever- 
green leaves.  Its  hard  and  heavy  wood  is  very  strong  and  durable, 
and  has  been  much  used  in  ship-building. 

Q.  chrysolepis,  the  Canon  Live  Oak  of  the  canons  and  mountain- sides 
of  California,  resembles  the  preceding  in  many  respects,  being  like  it 
nn  evergreen,  and  sometimes  attaining  a  height  of  from  twelve  to  six- 


480  BOTANY. 

teen  metres  or  more  (40-50  feet).  "It  furnishes  the  hardest  oak  wood 
of  the  Pacific  Coast,  and  is  used  in  making  ox-bows,  ax-handles,  etc." 
(Vasey). 

Q.  Suber,  the  Cork  Oak,  is  found  in  Southern  France,  Spain,  Italy, 
Sardinia,  and,  to  a  limited  extent,  in  Northern  Africa.  It  is  a  spread- 
ing topped  tree,  bearing  oval,  dentate  evergreen  leaves.  Certain  lay- 
ers of  cells  in  its  bark  retain  their  power  of  growth  for  a  long  time, 
and  give  rise  to  a  thick  mass  of  cork.  This  is  removed  every  eight  or 
ten  years  by  making  vertical  and  transverse  cuts  in  the  bark,  and  then 
peeling  off  all  but  the  inner  bark  layers.  Most  of  the  supply  of  cork 
comes  from  Spain  and  Southern  France.  The  tree  might  very  profit- 
ably be  grown  in  our  Southern  States  and  in  California. 

Q.  cerris,  the  Turkey  Oak  of  Southeastern  Europe,  is  a  fine  tree  with 
deciduous,  lobed  leaves,  and  bears  a  considerable  resemblance  to  our 
native  Q.  mavrocarpa,  from  which  it  differs,  however,  in  requiring  two 
years  to  mature  its  fruits.  Its  timber  is  much  used  for  ship-building 
and  other  purposes. 

(6)  Black  Oaks. 

In  this  are  the  Black  Jack  (Q.  nigra),  the  Red  Oak  (Q.  rrtbra}.  Scarlet 
Oak  (Q.  coccinea),  Quercitron  Oak,  (Q.  aceinea,  var.  tinctorial,  all  of 
the  Eastern  United  States.  The  timber  obtained  from  these  is  coarse- 
grained, and  not  so  durable  as  that  of  the  white  oaks ;  the  two  last  fur- 
nish a  yellow  dye,  Quercitron,  which  is  derived  from  the  bark.  Q.  agri- 
folia,  the  Field  Oak  of  California  is  a  broad-topped  evergreen  species. 
Its  wood  is  of  but  little  value. 

SECTION  II.,  the  Spiny -Cupped  Oak,  includes  but  a  single  species, 
found  in  California. 

Q.  densiflora,  the  California  Tan-bark  Oak.  This  is  a  beautiful  tree, 
often  thirty  metres  or  more  in  height  (100  feet),  with  curious  chestnut- 
like  fruits. 

The  remaining  sections  contain  eighty  to  ninety  species,  confined  en- 
tirely to  India,  China,  Japan,  and  the  Malay  Islands.  They  differ  in 
many  respects  from  our  oaks. 

Order  Juglandaceee.— The  Walnut  Family.  Trees  and  shrubs 
with  pinnately  compound  leaves  ;  fruit  a  dry  drupe,  containing  a  hard, 
one-seeded  nut  (Figs.  380-382).  This  family  includes  about  thirty  spe- 
cies, about  equally  divided  between  North  America  and  Asia.  They 
possess  an  acrid  aromatic  principle,  which  has  been  used  in  medicine. 

Juglans  regia,  the  Walnut  of  the  Old  World,  is  a  native  of  Asia 
Minor  and  the  country  eastward,  but  long  cultivated  in  all  parts  of 
Europe,  and,  to  some  extent,  in  this  country.  The  light  brown  wood  is 
highly  prized  in  England  for  cabinet-making,  the  manufacture  of  fur- 
niture, piano-cases,  gun-stocks,  etc.  Its  thin-shelled  nuts  are  highly 
esteemed,  and  are  imported  from  Europe  in  large  quantities  under  the 
name  of  "English  Walnuts."  (Figs.  375-82.) 

J.  nigra,  the  Blnck  Walnut  of  the  Eastern  United  States,  is  a  giant 


QUERN  ALES. 


481 


tree,  often  forty  to  fifty  metres  (130-160  feet)  in  height.  Its  dark  brown 
timber  is  fully  as  valuable  as  the  preceding,  and  is  used  for  the  same 
purposes.  It  is  exported  in  considerable  quantities  to  England.  Its 

FIGS.  375-82. — ILLUSTRATIONS  or  JUGLANS  REGIA. 
IHi* 


FIG.  380. 


FIG.  381. 


FIG.  382. 


Fig.  375.— Female  flower  cluster.  Fig.  376.  Female  flower.    Magnified. 

Fig.  377.-Female  flower  cut  vertically.    Magnified. 
Fig.  378.-Male  flower.    Magnified.  Fig.  379.— Male  flower  cluster. 

Fig.  380.-Ripe  fruit.  Fig.  381.— Emlocarp.  Fig.  382.— Seed. 


482  BOTANY. 

thick-shelled  and  stronger-tasting  nuts  are  occasionally  found  in  the 
markets. 

J.  cinerea,  the  White  Walnut*  or  Butternut,  of  the  Eastern  United 
States,  is  a  smaller  tree,  furnishing  a  valuable  lighter  colored  timber 
than  the  preceding. 

Two  small  species  occur  in  California,  Arizona,  and  Texas. 

Carya  aba,  the  Shell-bark  Hickory,  and  C.  sulcata,  both  large  trees, 
of  the  Eastern  United  States,  furnish  a  white,  tough,  and  hard  timber, 
useful  in  the  manufacture  of  agricultural  implements,  and  for  many 
other  purposes  where  great  strength  is  required.  It  is  not  well  adapted 
to  use  in  large  masses,  as  it  is  liable  to  early  destruction  through  decay 
and  the  ravages  of  wood-boring  insects.  The  fruits,  known  as 
"Hickory-nuts,"  and  highly  prized  for  eating,  are  found  in  our  mar- 
kets, and  are  also  exported  to  England. 

G.  olivceformis,  a  small  tree  of  the  Southern  States,  furnishes  a  thin- 
shelled  edible  fruit  known  as  the  "Pecan-nut." 

Other  species  of  Carya  furnish  valuable  timber,  and  from  the  nuts 
of  this  and  the  preceding  species  valuable  "nut-oils"  used  in  paint- 
ing are  obtained. 

571.  — Cohort  m.  Asarales.  Herbs,  with  mostly  mon- 
oclinous  flowers,  inferior  ovary,  and  seeds  with  integuments, 
containing  minute  embryo  usually  surrounded  with  endos- 
perm. 

Order  Rafflesiacese.— Parasites  upon  the  steins  and  roots  of  Dicoty- 
ledons. Twenty  or  more  species  are  known,  distributed  throughout 
the  hotter  parts  of  the  world. 

Rafflesia  Arnoldi,  of  Sumatra,  is  the  most  remarkable  member  of  the 
order.  It  consists  of  a  gigantic  parasitic  flower  nearly  a  metre  in  di- 
ameter (3  ft.),  with  five  mottled-red  spreading  petals.  It  is  parasitic 
upon  a  woody  climbing  plant  (Cissus  angustifolia)  nearly  related  to  the 
Vine,  and  in  its  growth  forms  scarcely  any  stem,  developing  almost  at 
once  into  a  giant  flower-bud.  It  was  discovered  in  1818  by  Dr.  Arnold. 

Order  Aristolochiacese. — Mostly  tropical  herbs,  including  about 
200  species.  Three  species  of  Asarum,  and  three  of  Aristolochia  occur 
in  the  United  States. 

572.— Cohort  IV.  Nepenthales.  Climbing  shrubs,  with 
diclinous  flowers,  a  superior  three  to  four-celled  ovary,  whose 
many  seeds  contain  an  endosperm. 

Order  Nepenthaceae. — Plants  of  the  East  Indies  and  Australia,  of 
ten  or  twelve  species,  all  belonging  to  the  genus  Nepenthes.  The 
leaves  are  prolonged  into  a  slender  tendril  like  organ,  upon  whose  ex- 
tremity there  develops  a  hollow  closed  body,  which  finally  becomes 
open  by  the  separation  of  its  apex  in  such  a  manner  as  to  form  a 
hinged  lid  (Fig.  383,  d,  e,  /).  In  the  cavities  of  these  pitchers,  as  they 


PIPERALES. 


483 


are  called,  a  watery,  slightly  acid  fluid  is  secreted  ;  upon  their  borders 
are  secreted  honey  or  nectar  drops,  which  attract  insects,  and  these  fall 
ing  into  the  fluid  within  are  soon  dissolved  by  it,  and  then  absorbed  by 
the  plant  for  its  nour- 
ishment. 

573.— Cohort  V. 
Piperales.  Mostly 
herbs,  with  spiked 
flowers  and  superior 
one-celled  and  one- 
seeded  ovary. 

Order  Ceratophyl- 
leee. — Aquatic  herbs  of 
the  Northern  Hemi- 
sphere. 

Order  Chlorantha- 
cese.— Shrubby  plants, 
mostly  of  the  tropics. 

Order  Piperacese. — 
The  Pepper  Family. 
Herbs,  shrubs,  or  small 
trees,  almost  confined  to 
the  tropics  ;  generally 
with  a  pungent  and 
aromatic  principle. 
Over  1000  species  are 
known. 

We  have  one  species 
of  Saururus  in  the  East- 
ern, and  one  of  Anemi- 
opsis  in  the  Southwest- 
ern United  States. 

Two  tropical  genera, 
Piper  and  Peperomia, 
include  nearly  all  the 
species,  the  first  con- 
taining 620  and  the  sec-  short  petiole ; ~  b,  blade  or  expanded  part ;  of  leaf ;  c,  ten- 
nnH  989  dril-like  prolongation  of  midrib  ;  d,  «,  pitcher  ;/,  its 

ond  6V£.  lid     In  t£e  other  ]eaf  wh,ch  jg  youn?er,  the  lid  has  not 

Piper    nigrum    is    a    yet  separated  from  the  apex  of  the  pitcher.— After  Du- 
climbing    East    Indian    cl 

plant,  with  heart-shaped  leaves  ;  it  bears  spikes  of  berries,  which, 
when  gathered  green  and  dried,  constitute  the  Black  Pepper  of  com- 
merce. The  ripe  berries,  when  dried,  constitute  White  Pepper.  Pep- 
per is  now  grown  in  the  West  Indies. 


m._Two  ,eave8  of 


484  BOTANY. 

P.  Cubeba,  whose  dried  unripe  berries  are  known  in  pharmacy  as 
Cubebs,  is  a  native  of  the  East  Indies. 

P.  Betle,  of  the  East  Indies,  is  the  Betel  Pepper,  whose  bitter  aro- 
matic leaves  are  mixed  with  Areca-nut  and  lime  to  form  a  masticatory. 
(See  Betel  Palm,  p.  466.) 

From  the  thick  rhizome  of  P.  methysticum  the  inhabitants  of  many 
of  the  Pacific  islands  make  a  disgusting  driuk  which  is  very  intoxica- 
ting. 

574.— Cohort  VI.  Euphorbiales.  Plants  with  mostly 
diclinous  flowers,  with  a  superior  two  to  many-celled  ovary  ; 
seeds  containing  endosperm. 

Order  Lacistemacese.     Shrubs  of  tropical  America. 

Order  Geissolcmeae,  containing  a  single  shrub,  of  Southwestern 
Africa. 

Order  Penaeaceae.     Evergreen  shrubs  of  South  Africa. 

Order  Euphorbiacese.— The  Spurge  Family.  This  vast  group  of 
upwards  of  3000  species  can  not  be  defined  by  anyone  character.  They 
may  generally  be  distinguished  by  their  three-celled  ovaries  and  milky 
juice,  although  neither  of  these  characters  is  universal  throughout  the 
order.  The  species  range  in  size  from  small  herbs  to  gigantic  trees, 
and  are  distributed  throughout  all  climates  except  beyond  the  Arctic 
Circle.  They  are  much  more  abundant,  however,  in  tropical  countries 
than  elsewhere.  With  few  exceptions  they  possess  an  acrid  principle, 
which,  is  often  poisonous. 

Many  of  the  species  are  of  economic  importance,  a  few  of  which  only 
can  be  mentioned  here. 

Manihot  palmata  and  M.  utilissima,  slender  plants  of  tropical  Amer- 
ica, and  now  cultivated  in  many  tropical  countries,  have  thick  starchy 
roots.  The  starch,  separated  and  washed,  is  imported  under  the  name 
of  Brazilian  Arrowroot.  Tapioca  is  prepared  by  heating  the  separated 
and  washed  starch  upon  hot  plates.  Cassava  is  made  from  the  crushed 
roots  by  drying  the  pulp  without  separating  the  starch.  These  three 
substances  are  highly  nutritious,  and  are  much  used  as  food  by  the 
natives,  and  are,  moreover,  largely  imported  into  this  country.  Their 
value  is  all  the  more  remarkable  from  the  fact  that  the  root  of  the 
second  named  species  above  is  in  its  raw  state  deadly  poisonous. 

Rieinvs  communis,  the  Castor  Oil  plant,  a  native  of  India,  is  now 
widely  grown  for  its  oily  seeds,  from  which  Castor  Oil  is  obtained  by 
pressure.  It  is  extensively  grown  in  the  Mississippi  Valley.  In  Ger- 
many it  is  grown  for  its  leaves,  which  are  fed  to  silkworms.  It  is  a 
beautiful  ornamental  plant,  and  when  grown  for  this  purpose  is  called 
the  Palma  Christa. 

Croton  Oil  from  Croton  Tiglium,  and  Pinhoen  Oil  from  Jatropha  Cur- 
cas,  are  drastic  medicines.  Gum  Euphorbium,  the  dried  milky  juice 


EUPHORBIALES.  485 

of  various  African  and  Indian  species  of  Euphorbia,  Cascarilla  Bark  and 
Melambo  Bark  from  species  of  Croton  in  tropical  America,  are  more  or 
less  known  iu  pharmacy. 

Hevea  Guianeims  and  other  species  of  the  genus,  natives  of  the 
northern  part  of  South  America,  furnish  the  important  substance 
Caoutchouc,  or  India  Rubber.  The  trees  are  from  fifteen  to  thirty 
metres  in  height  (50  to  100  ft.),  and  bear  trifoliate  leaves  resembling 
those  of  the  Scarlet-runner  bean  in  size  and  shape.  The  natives  make 
incisions  into  the  trees,  from  which  the  milky  juice  exudes,  and  this 
evaporated  constitutes  the  crude  Caoutchouc.  By  heating  the  crude 
product  with  sulphur  it  is  hardened,  and  is  then  known  as  "  Vulcan- 
ized rubber." 

Exccecaria  sebifera,  the  Tallow  tree  of  China,  now  cultivated  in  the 
warmer  parts  of  America,  has  its  seeds  coated  with  a  white  greasy  sub- 
stance, which  yields  a  valuable  tallow  from  which  candles  are  made. 

Aleurites  Moluccana,  the  Candle  Nut  tree  of  India  and  the  Pacific 
islands,  produces  a  large  oily  fruit,  which  is  itself  burned  and  used  as 
a  candle,  or  from  which  a  valuable  oil  is  extracted. 

The  most  valuable  timber  of  the  order  is  furnished  by  Buxus  semper- 
virens,  the  Box  tree  of  Europe  and  Asia.  It  is  a  small  evergreen 
tree,  with  a  very  hard  yellowish  wood,  invaluable  in  wood  engraving, 
the  manufacture  of  mathematical  instruments,  etc.  Our  chief  supply 
comes  from  the  Mediterranean  ports.  A  dwarf  variety  of  this  species 
is  used  for  bordering  garden  walks. 

African  Teak,  a  very  heavy  and  hard  wood  from  Africa,  is  supposed 
to  be  derived  from  Oldfieldia  Africana,  which  has  been  doubtfully  re- 
ferred to  this  order. 

Among  the  plants  grown  for  ornament  are  many  species  of  Euphor- 
bia, an  immense  genus  of  700  species,  distributed  very  widely  ;  in 
Africa  they  assume  a  Cactus-like  aspect,  having  thick  succulent  stems. 
These  and  many  other  species  are  to  be  found  in  conservatories.  The 
curious  Xylophytta,  with  flat  leaf-like  branches,  bearing  flowers  upon 
their  edges,  is  also  common. 

The  Sand  Box  tree  of  tropical  America  bears  a  curious  many-celled 
fruit  which  when  dry  explodes  with  a  loud  report. 

The  juice  of  many  of  the  species  is  poisonous  when  dropped  upon  the 
ekin,  or  into  a  wound.  The  Manchineel  tree  (Hippomane  Mancinelld) 
of  South  Florida  and  the  West  Indies  is  extremely  poisonous,  but  many 
of  the  stories  told  of  it  are  fabulous. 

Zebra  Poison  is  the  name  applied  to  Euphorbia  arborea  ;  branches  of 
it  placed-  in  water  render  it  sufficiently  poisonous  to  kill  the  animals 
which  drink  it. 

575.— Cohort  VII.  Amentales.  Woody  plants,  with  di- 
clinous flowers,  mostly  in  catkins ;  the  one  or  two-celled 
ovary  superior,  and  the  seeds  with  no  endosperm. 


486  BOTANY. 

Order  Salicaceee. — The  Willow  Family.  Dioecious  trees  and  shrubs 
with  naked  flowers — i.e.,  the  perianth  wanting.  The  species,  of  which 
there  are  180,  are  principally  found  in  the  North  Temperate  and 
Arctic  Zones ;  beyond  the  tropics  they  are  rare,  and  none  occur  in 


FIGS.  884-9.— ILLUSTRATIONS  OF  SALIX  CAPR^A. 


Fio.  386.  FIG.  387. 

Fig.  384.— Male  catkin  and  separate  flower. 

Fig.  385.-Female  catkin.  Fig.  386. -Female  flower.    Magnified. 

Fig.  387. -Cross-section  of  ovary.    Magnified. 

Fig.  388.-Ripe  fruit  and  seed.    Magnified.     Fig  389.-Embryo.    Magnified. 


Australia  and  the  South  Pacific  Islands.  They  contain  a  bitter  astrin 
gent  principle  useful  in  medicine  as  a  febrifuge. 

Two  genera  only  are  known. 

Salix  verminalis,  S.  purpurea,  S.  caprcea,  and  other  species  of  the 
Old  World,  are  cultivated  for  basket-making. 


AMENTALES.  487 

S.  Biibylonica,  the  weeping  willow  of  Persia,  is  well  known  under 
cultivation. 

8.  alba  and  other  large  species  of  Europe  furnish  a  light  firm  wood, 
much  used  for  many  purposes. 

By  charring  the  wood  a  fine  charcoal  is  obtained,  much  used  in  the 
manufacture  of  gunpowder.  In  the  prairies  of  the  Mississippi  Valley 
the  species  last  named  is  planted  in  compact  rows  to  serve  for  hedges 
and  to  break  the  force  of  the  violent  winds. 

Some  of  the  larger  of  our  many  native  species  might  profitably  be 
used  for  their  light  timber,  which  in  some  cases  is  quite  durable. 

Populus  Canadenfds,  the  Cottonwood  of  North  America,  is  a  very 
large  tree,  whose  white  wood  is  suited  to  many  manufacturing  pur- 
poses. 

The  "  Lombardy  Poplar,"  a  variety  of  P.  nigra,  and  a  native  prob- 
ably of  Western  and  Northern  Asia,  and  the  Abele  tree  (P.  alba)  of 
Europe,  are  commonly  grown  on  large  grounds. 

Order  Casuarineae. — Leafless  trees,  with  pendulous  Equisetum-like 
jointed  stems.  Twenty  five  species,  mostly  natives  of  Australia,  are 
known.  Some  of  them  are  large  enough  to  supply  a  valuable  timber 
for  ship-building,  and  many  are  favorites  for  ornamental  purposes  in 
Australia. 

Order  Myricaceae. — Monoecious  or  dioecious  shrubs,  often  with  a 
glandular  waxy  pubescence.  The  thirty  to  thirty-five  species  are 
widely  distributed  throughout  the  North  Temperate  Zone,  and  in  trop- 
ical Asia  and  South  Africa. 

The  berries  of  Myrica  cerifera,  the  Bayberry,  of  the  Eastern  United 
States,  and  other  species  in  Europe  are  covered  with  a  wax,  which  is 
gathered  and  made  into  candles. 

Order  Platanacese. — The  Plane  Tree  Family.  A  small  group  of 
five  monoecious  trees,  with  the  flowers  in  globose  catkins. 

Platanus  occidentals,  the  Phme  tree,  Buttonwood,  or  Sycamore  of 
the  Eastern  United  States,  is  a  large  tree  with  thin  white  bark.  Its 
reddish  wood  is  valuable,  and  should  be  more  used.  A  nearly  related 
species  occurs  in  California  and  two  in  Mexico.  The  fifth,  P.  oi-iental- 
is,  is  the  only  Old  World  species. 

Order  Betulaceee. — The  Birch  Family.  Monoecious  trees  with 
flowers  in  slender  catkins.  The  species,  forty  or  more  in  number,  are 
iound  throughout  the  North  Temperate  Zone,  and  in  South  America. 

Betitia  alba,  of  Northern  Europe,  Northern  Asia,  and  North  America, 
is  a  useful  species.  Its  wood  is  valuable  for  fuel,  use  in  manufactures, 
and  for  making  into  charcoal.  Its  bark  is  made  into  shoes,  boxes,  etc. ; 
it  is  used  in  tanning  leather,  and  from  it  by  distillation  an  oil  is  ob- 
tained which  gives  to  Russia  leather  its  peculiar  scent.  The  people  in 
the  high  north  latitudes  also  use  the  cellular  and  starchy  part  of  the 
bark  for  food. 


488  BOTANY. 

The  bark  of  B.  papyracea,  of  the  Eastern  United  States,  is  used  by 
the  Indians  for  making  their  "  birch  bark  canoes." 

The  wood  of  species  of  Alnus,  the  Alders,  is  very  durable  when 
placed  under  the  ground  or  water.  It  is  also  made  into  wooden  bowls 
and  other  domestic  utensils,  and  is  in  some  places  grown  for  making 
into  charcoal. 

576.— Cohort  VIII.  Urticales.  Mostly  diclinous  plants, 
with  superior  one-celled  ovary,  and  single  seed  mostly  with 
an  endosperm. 

Order  TJlmacese.— The  Elm  Family.  Trees  or  shrubs  of  the  North 
Temperate  Zone,  having  mostly  monoclinous  flowers,  and  a  watery 
juice.  About  one  hundred  and  thirty  species  are  known. 

Ubmvs  campestris,  the  common  Elm  of  Europe  and  Western  Siberia, 
is  a  large  tree,  thirty  to  forty  metres  (100  to  130  ft.)  high.  Its  timber  is 
valuable  for  works  underground  or  in  water,  and  is  besides  much  used 
by  wheelwrights.  The  tree  is  common  in  American  gardens. 

V.  Americana,  the  American  White  Elm  of  the  Eastern  United 
States,  and  now  much  grown  in  Europe,  is  one  of  our  finest  looking 
trees,  and  deservedly  popular  as  an  ornament  in  large  grounds.  Its 
timber  is  valuable  when  used  entirely  under  water  or  in  the  ground, 
or  when  kept  continuously  dry  ;  otherwise  it  decays  rapidly. 

U.  fulva,  the  Slippery  Elm  of  the  Eastern  United  States,  supplies  a 
valuable  timber,  and  its  mucilaginous  inner  bark  is  used  for  medical 
and  surgical  purposes. 

Celtis  occidentalis,  the  Hackberry  of  the  Eastern  United  States,  is  a 
lofty  tree  which  furnishes  a  white  hard  timber,  which  is  not,  however, 
very  durable. 

Order  Cannabinese. — This  contains  the  two  dioecious  herbs,  the 
Hemp  and  the  Hop. 

Cannabis  sativa,  the  Hemp,  is  a  tall  herb,  two  to  three  metres  (7  to 
10  ft.)  in  height,  indigenous  in  the  northern  parts  of  India,  but  now 
generally  cultivated  in  all  temperate  and  warm  regions.  Under  the 
names  of  gunja,  bhang,  churrus,  haschisch,  etc.,  the  natives  of  India  and 
Central  Africa  use  the  dried  leaves,  stems,  flowers,  and  the  resinous 
matter  which  develops  on  the  plant.  When  smoked,  or  drank  as  an 
infusion,  these  are  highly  intoxicating.  The  fibre  obtained  from  its 
bark  is  strong,  and  much  used  for  cordage. 

Humulus  Lupulus,  the  Hop,  a  native  of  temperate  Europe,  Asia,  and 
North  America,  is  grown  for  its  bitter  principle,  Lupulin,  which  de- 
velops in  the  female  flower  clusters,  and  which  is  much  used  in  the 
manufacture  of  beer,  ale,  etc. 

Order  Moracese.— The  Mulberry  Family.  Trees  or  shrubs,  con- 
taining a  milky  juice.  The  order  contains  between  800  and  1000  spe- 
cies, and  they  are  for  the  greater  part  natives  of  the  tropics.  Many 


URTICALES. 


489 


of  them  contain  an  acrid  poisonous  principle,  while  some  are  not  only 
innoxious,  but  afford  wholesome  food. 

Artocarpus  iricita,  the  Bread  Fruit  tree,  a  native  of  the  Pacific  Is- 
lands, and  now  common  in  tropical  countries,  attains  a  height  of  from 
six  to  nine  metres  (20  to  30  ft.).  The  fleshy  receptacle  and  agglomerated 
carpels  form  a  mass  as  large  as  a  man's  head.  This  "  fruit,"  when 
gathered  a  little  before  it  is  ripe,  and  baked,  looks  and  tastes  much 
like  bread,  and  is  largely  eaten  by  tropical  people.  The  Jack  Fruit  of 
India  (A.  integnfolius)  is  similar,  but  not  so  palatable. 

Ficus  Carica,  the  Fig,  a  native  of  Western  or  Southern  Asia,  has 

FIGS.  390,  91.— ILLUSTRATIONS  OF  HORACES. 


Fig.  390.— Flashy  concave  receptacle  of  Ixnstenia,  bearing  male  and  female  flowers. 
Fig.  391.— Fleshy  closed  receptacle  of  Ficus,  cut  vertically,  containing  male  flowers 
above  and  female  below. 

been  cultivated  for  ages.  It  is  now  found  in  all  tropical  and  sub-trop- 
ical countries.  It  is  grown  in  the  Southern  United  States  and  in  Cali- 
fornia. The  tree  attains  a  height  of  from  five  to  six  metres  (16  to  20 
ft.),  and  bears  pear-shaped  closed  receptacles  (Fig.  391),  inside  of  which 
are  the  minute  flowers.  The  ripened  and  dried  receptacles  constitute 
the  FigB  of  commerce.  Our  supply  comes  mainly  from  the  Mediter- 
ranean Basin. 

Gcdactodendron  utile  (Brosimum  utUe),  a  tall  tree,  twenty-five  metres 
high  (80  ft.),  of  Venezuela,  whose  milky  juice  is  used  by  the  natives  as 
a  substitute  for  milk,  to  which  it  bears  a  close  resemblance.  The  tree 
>s  hence  called  the  Cow  Tree. 


490  BOTANY. 

Morus  nigra,  the  Mulberry  tree  of  Persin,  is  now  cultivated  in  Eu- 
rope and  the  United  States  for  its  edible  fruit  masses.  Its  leaves  are 
used  to  feed  to  silkworms,  but  not  to  so  great  an  extent  as  those  of 
M.  alba,  the  White  Mulberry,  which  has  been  used  from  time  imme- 
morial for  this  purpose  in  China. 

Jf.  rubra,  a  native  of  the  Eastern  United  States,  bears  valuable 
fruits. 

Several  of  the  trees  of  the  order  yield  Caoutchouc.  The  most  im- 
portant of  these  are  Ficus  elastica  of  India,  and  Castilloa  elastica  of 
Mexico  and  the  West  Indies  ;  the  first  named  is  a  common  greenhouse 
plant. 

Gum  Lac  is  a  resinous  exudation  collected  from  an  Indian  species  of 
Ficus,  whose  branches  have  been  punctured  by  an  hemipterous  insect, 
Coccus  lacca. 

The  wood  of  many  species  is  valuable. 

Brosimum  Ouianensis,  of  Guiana,  produces  the  beautifully  mottled 
and  streaked  Snakewood,  much  prized  by  cabinetmakers,  and  for 
making  bows. 

Madura  aurantiaca,  a  tree  eight  to  fifteen  metres  (25  to  50  ft.)  high, 
growing  in  Arkansas,  Texas,  etc.,  supplies  a  very  hard  wood  used  by 
the  Indians  for  making  bows,  hence  one  of  its  names,  "  Bow-wood." 
Under  the  name  of  Osage  Orange,  it  is  much  used  as  a  hedge  plant. 
Its  wood  yields  a  coloring  matter  used  as  a  dye,  and  from  M.  tinctoria, 
of  the  West  Indies,  the  dye  known  as  Fustic  is  obtained. 

The  bark  of  many  species  yields  tenacious  fibres  ;  thus  from  the 
Paper  Mulberry  (Broussonetia  papyri/era),  a  Chinese  and  Japanese  tree 
eight  to  fifteen  metres  (25  to  50  ft.)  in  height,  the  Chinese  make  paper, 
and  the  Pacific  Islanders  make  cloth.  One  of  the  most  remarkable  is 
the  Sack  tree  (Antiaris  saccidora)  of  Western  India;  its  bark  is  so 
tenacious  that  after  beating,  it  may  be  removed  in  sections,  which  are 
used  for  sacks  for  carrying  rice,  etc. 

The  Upas  Tree  of  Java  (Antiaris  toxicatia)  is  poisonous,  but  it  is  by 
no  means  as  virulent  as  it  has  been  described.  It  frequently  grows  in 
volcanic  valleys  partially  filled  with  carbon  dioxide  and  other  noxious 
gases,  and  to  this  fact  is  doubtless  due  the  marvellous  stories  told  of  it. 
However,  from  its  juice  the  natives  prepare  a  deadly  poison  for  their 
arrows. 

The  Banyan  Tree  (Ficus  Indica)  is  remarkable  for  its  numerous  ad- 
ventitious roots,  which  grow  down  from  its  horizontal  branches,  and 
thus  enable  it  to  extend  its  top  very  greatly.  One  on  the  Neibudda, 
with  three  hundred  and  twenty  of  such  supporting  roots,  covers  an 
area  two  hundred  metres  (650  ft.)  in  diameter. 

Order  TJrticace».—  The  Nettle  Family.  Herbs,  shrubs,  or  trees, 
with  a  limpid  juice  ;  they  occur  in  all  climates,  but  mostly  in  the 
tropics.  More  than  five  hundred  species  are  known.  Many  of  the 
species  possess  a  valuable  fibrous  bark.  (Figs.  392-7.) 


DAPHNALES. 


491 


FIGS.  392-7.— ILLUSTRATIONS  OP  UBTICA  URENS. 


Bwhmeria  nivea,  the  China  Grass  or  Hamie,  a  perennial  herbaceous 
plant,  may  fairly  rival  Flax  in  the 'fine  and  durable  fibres  it  produces. 
It  has  been  introduced  into  the  Southern  United  States  and  California. 
There  is  still  some  difficulty  in  separating  the  fibres  from  the  woody 
portions  of  the  plant,  and  this  has  prevented  its  more  extensive  use. 

The  Stinging  Nettles  include  ten  genera,  of  which  the  most  impor- 
tant are  Urtica,  which  includes  our  common  species,  and  Laportea, 
represented  by  our  Wood  Nettle  ;  to  the  latter  belongs  the  Tree  Nettle, 
L.  gigas,  of  Australia,  which  reaches  a  height  of  from  fifteen  to  forty 
metres  (50  to  130  ft.),  and  whose  sting  is  so  severe  as  to  produce  dan- 
gerous results. 

577.  —  Cohort 
IX.  Daphnales. 
Mostly  shrubs  or 
trees,  with  mono- 
clinous  flowers  ; 
ovary  superior, 
one-celled,  with  a 
single  seed  con- 
taining no  endo- 
sperm. 

Order  Protea- 
ceae.— A  family  of 
about  1000  species, 
confined  almost  en- 
tirely to  the  South- 
ern Hemisphere,  and 
occurring  in  greatest 
abundance  in  A  us- 
tralia  and  South 
Africa.  Many  spe- 
cies, especially  of  the 

genus  Banksia,  are  cultivated  in  conservatories, 
ble  timber. 

GreviUea  robusta,  the  Silk  Oak  of  Australia,  attains  a  height  of 
twenty-four  to  thirty  metres  (80  to  100  ft.),  with  a  diameter  of  two 
metres  or  more,  and  supplies  valuable  timber. 

Knightiaexcelsa  is  a  valuable  New  Zealand  timber  tree  thirty  metres 
(100  ft.)  or  more  in  height. 

Lewadendron  argenteum,  the  Silver  Tree  of  the  Cape  of  Good  Hope, 
has  silvery  lanceolate  leaves  ;  its  wood  is  much  used  for  fuel. 

Protect  grandiflora,  the  "  Wagen-boom  "  of  the  same  region,  is  used 
by  wheelwrights  in  the  manufacture  of  wagon  wheels. 

Order  Eleeagnaceee. — A  small  order,  of  sixteen  species,  of  trees  or 


FIG.  394. 


FIG.  395. 


FIG.  396. 
Fig.  392.— Male  flower.    Magnified 
Fig.  393.— Diagram  of  male  flower. 
Fig.  394. -Female  flower.    Magnified. 
Fig.  395.— Diagram  of  female  flower. 
Fig  396. -Seed.    Magnified. 
Fig-  397.— Section  of  seed.    Magnified. 


FIG.  397. 


A  few  furnish  valua- 


492 


BOTANY. 


shrubs,  found  mostly  ir,  the  mountains  of  Southern  Asia.  The  Oleaster 
(Elaagnus  hortensis)  of  Southern  Europe  is  there  much  planted  for  its 
odoriferous  flowers ;  it  is  occasionally  planted  in  this  couutry. 

Shtpheidia  Canadensis,  of  the  Northeastern  United  States,  and  S. 
argentea,  the  Buffalo-Berry  of  the  Rocky  Mountains  and  the  Great 
Plains,  are  frequently  cultivated  for  their  acid  fruits,  which  are  about 
as  large  as  currants. 

Order  Hernandieae,  including  a  few  tropical  trees. 


FIGS.  398-402.— ILLUSTRATIONS  or  LAURUS  NOBILIS. 


Fig.  m-Male  flower.    Magnified. 
Fig,  400.— Female  flower.    Magnified. 
Fig.  402.-Diagram  of  female  flower. 


FIG.  402. 


Fig.  399. — Diagram  of  male  flower. 
Fig.  401. — Section  of  female  flower. 


Order  Thymelaeaceee. — Shrubby  plants,  mostly  of  the  Southern 
Hemisphere.  Of  the  378  species  we  have  in  the  United  States  but  one 
representative,  viz.,  the  Moose- wood  or  "  Wicopy"  (Dirca  palustris),  a 
small  shrub  with  exceedingly  tough  bark. 

Daphne  Mezereum,  a  poisonous  phrub  of  Europe,  is  frequently  culti- 
vated here  for  its  sweet-smelling  flowers. 

The  bark  of  many  species  is  used  in  their  native  countries  for  making 


LA  URALES. 


493 


fabrics,  cordage,  etc.     Lagetta  lintearia,  of  Jamaica,  is  the  Lace-Bark 
Tree,  so  called  on  account  of  its  delicate  inner  bark. 

578.— Cohort  X.  Laurales. — Herbs,  shrubs,  and  trees, 
with  mostly  diclinous  flowers  ;  ovary  superior,  one-celled, 
the  single  seed  sometimes  with,  and  sometimes  without 
endosperm. 

Order  Lauraceae. — The  Laurel  Family.     Aromatic  trees  and  shrubs 

FIGS.  403-5.— ILLUSTRATIONS  OP  MTRISTICA  FRAGRANS. 


FIG.  403.  FIG.  405. 

Fig.  403.  -  Frnit,  showing  seed  and  aril.          Fig.  404.— Seed  and  aril. 
Fig.  405.  -Seed  cut  vertically,  showing  embryo  below. 

(rarely  parasitic  herbs)  with  free  stamens,  and  a  pendulous  seed  with- 
out endosperm.  About  1000  species  are  known,  occurring  in  the  trop- 
ical and  temperate  climates  of  both  hemispheres. 

Laurus  nobilis,  the  Bay  or  Laurel  of  Southern  Europe,  is  a  fine 
spread  ing-topped  evergreen  tree,  twelve  to  fifteen  metres  (40  to  50  ft.) 
high.  In  ancient  times  its  leaves  were  used  to  crown  heroes,  but  now 


494  BOTANY. 

they  are  made  use  of  in  flavoring  custards,  puddings,  etc.,  and  are  put 
into  boxes  of  figs  to  give  them  a  factitious  flavor.    (Figs.  398-402.) 

Umbellularia  Californica  (Tetranthera  California*),  the  California 
Laurel,  resembles  the  preceding,  and  like  it  is  evergreen.  Its  wood  is 
used  in  cabinet-making. 

Persea  gratusima,  a  small  West  Indian  tree,  produces  a  delicious 
fruit  called  Avocado-  or  Alligator-Pear. 

Among  the  aromatic  products  are  Cinnamon,  the  bark  of  Cinna- 
momum  Zeylanicum,  a  small  tree  of  Ceylon  ;  Cassia  Bark  and  Cassia 
buds,  from  G.  Cassia,  of  Ceylon  ;  Camphor,  a  gummy  matter  distilled 
from  the  wood  of  C.  Camphora,  a  tree  of  China  and  Japan;  Sassafras 
Bark,  from  Sassafras  ojficinale,  of  the  Eastern  United  States. 

The  wood  of  the  two  last-named  trees  is  valuable  in  cabinet-making, 
as  is  also  that  of  the  Red  Bay  (Persea)  of  the  Southern  United  States. 

Nectandra  Rodiei.  the  Greenheart  Tree  of  Guiana,  is  a  large  tree 
furnishing  an  exceedingly  heavy,  dark  colored,  and  durable  timber, 
highly  valued  in  naval  constructions. 

Order  Myristicacese.— The  Nutmeg  Family.  Aromatic  trees,  with 
monadelphous  stamens,  and  an  erect  seed  containing  endosperm.  The 
seventy -five  species  are  all  tropical,  and  most  of  them  occur  in  the  In- 
dian region.  They  all  belong  to  the  genus  Myris  ica. 

Myristica  fragrans,  the  Nutmeg  Tree  of  the  Malay  Archipelago,  at- 
tains a  height  of  six  to  nine  metres  (20  to  30  ft.)  ,  it  bears  a  fleshy  fruit 
of  the  size  of  a  walnut  and  inside  of  this  is  a  large  seed  covered  with  a 
red,  branching  aril  (Figs.  403-4).  The  seed,  deprived  of  its  integu- 
ments, is  the  nutmeg  of  commerce,  while  the  dried  aril  is  the  Mace, 
both  well  known  condiments. 

Some  of  the  other  species  are  occasionally  used,  but  they  are  much 
less  valuable. 

Order  Monimiaceae. — Aromatic  trees  or  shrubs  of  the  tropics  and 
south  temperate  zone.  About  150  species  are  known.  The  Tasmnnian 
"Sassafras  Tree"  (Afherosperma  moschata),  the  Australian  "  Sassafras 
Tree"  (Doryphora  Sassafras),  and  the  New  Zealand  "Sassafras" 
(Lauretta  Nova  Zelandice),  are  large  trees  thirty  to  forty-five  metres 
(100  to  150  ft.)  high,  whose  timber  is  valuable  for  ship-building. 

579.— Cohort  XT.  Chenopodiales.  Monoclinous  (rarely 
diclinous)  herbs  or  shrubs ;  ovary  superior,  one-celled,  the 
single  seed  containing  endosperm. 

Order  Paronychieee.— A  small  group  of  mostly  herbaceous  plants, 
the  flowers  generally  with  both  sepals  and  petals  ;  the  latter,  however, 
rudimentary.  The  order  has  close  affinities  with  Caryophyllacese,  of 
which  it  should  probably  be  considered  a  sub-order. 

Order  Basellacese.— Herbaceous,  often  climbing  plants  of  the 
tropics.  One  epecies  from  South  America  (Boumngaultia  baselloides) 


V HEN  0  PODIA  LES. 


is  cultivated  as  an  ornamental  climber  under  the  name  of  Madeira 
Vine.  The  starchy  tubers  of  another  species,  Uducus  tuberosus,  are 
used  in  Peru  as  substitutes  for  the  potato. 

Order  Chenopodiacese. — Herbs,  shrubs,  or  rarely  trees,  whose 
flowers  have  an  herbaceous  perianth.  About  500  species,  distributed 
in  all  climates,  are  known.  (Figs.  406-11.) 

Beta  vulgaru,  the  Common  Beet,  is  a  native  of  Southern  Europe. 
The  Sugar  Beet  and  Mangel  Wurzel  are  only  varieties  of  the  Common 
Beet;  the  first  is  extensively  cultivated  in  France  for  the  sugar  which 

FIGS.  406-10. — ILLUSTRATIONS  OF  BETA  VULGABIS. 


FIG.  408. 

Fig.  406.-Flower.    Magnified. 
Fig.  408.— Section  of  flower.    Magnified. 
Fig.  410.-Seed.    Magnified. 


Fig.  407.— Diagram  of  flower. 
Fig.  409.-Three  fruits.    Magnified. 


is  obtained  from  its  sweet  juice  ;  its  cultivation  in  this  country  is  yet 
in  its  infancy. 

Cfienopodium  Qiiinon,  a  Peruvian  annual,  is  cultivated  in  Western 
South  America  for  itn  nutritions  seeds,  which  are  ground  into  meal,  and 
used  as  an  article  ot  food. 

C.  ambroyioidcs,  Worm  seed,  from  tropical  America,  used  somewhat 
in  medicine,  and  other  species  of  the  genus,  have  become  common  weeds 
in  fields  and  gardens. 

Spinaftia  oleracea,  Common  Garden  Spinach,  is  an  Oriental  plant 
much  cultivated  as  a  pot  herb. 


496 


BOTANY. 


Order  Amarantaceee.— Herbs,  rarely  shrubs,  whose  flowers  have  a 
ecarious  perianth.  The  order,  which  contains  about  500  species,  is 
mostly  tropical,  a  few  occurring  in  temperate  climates,  but  none  at  all 
in  cold  ones. 

In  India  some  of  the  species  are  cultivated  for  their  starchy  seeds, 
which  are  used  for  food. 

veral  species  are  cultivated  with  us  for  their  ornamental  foliage, 
(Achyranthes)  or  their  colored  inflorescence,  e.g., 
Cock's  Comb  (Celosia),  Globe  Amaranth  (Gomphre- 
na),  etc. 

Amarantus  retroflexus  and  A.  albus,  are  common 
weeds  in  fields ;  the  latter,  in  the  prairie  region, 
grows  in  a  globular  form,  and  in  the  autumn  breaks 
off  at  the  root,  and  is  blown  for  miles  across  the 
country.  On  account  of  this  habit  of  growth  it  is  called  the  "  Tumble 
Weed." 

Order  Polygonaceae. — The  Buckwheat  Family.  Herbs,  shrubs,  or 
rarely  trees,  mostly  with  sheathing  stipules  and  knotted-jointed  stems  ; 
perianth  often  petaloid.  The  600  species  constituting  the  order  are 
mostly  natives  of  temperate  regions. 

Ffigopyrum  esculentum,  Buckwheat,  a  native  of  Central  or  Northern 

FIGS.  412-16.— IJLLUSTBATIONS  OP  FAGOPTBUM  ESCULBNTUM. 


Fig.  411.— Section 
of  seed  of  Chenopo- 
dium.  Magnified. 


Fie.  412. 


Fig.  412  —Flower.    Magnified. 
Fig.  414.— Pistil.    Magnified. 


Fig.  413. — Diagram  of  flower. 
Fig.  415.— Fruit      Magnified. 


As'n,  is  now  extensively  grown  in  Europe  and  America  for  its  nutri- 
tious seeds,  and  for  its  honey-producing  flowers  (Figs.  412-15.) 

Polygonum  amphibium,  var.  terrestre,  a  native  of  the  United  States, 
has  been  used  in  the  Mississippi  valley  as  a  substitute  for  bark  in  the 
process  of  tanning.  It  contains  a  considerable  quantity  of  tannin. 

RTieum  officinale,  Oriental  Rhubarb,  is  a  native  of  Southeastern 
Asia ;  its  roots  constitute  the  officinal  Rhubarb.  Other  species  are 
often  used  as  substitutes. 


LAMIALES.  497 

R.  Rhaponticutn,  a  native  of  Western  Asia,  is  commonly  grown  in  \ 
gardens  under  the  name  of  "Pie  Plant,"  its  petioles  are  used  for  the  ; 
pleasant  acid  they  contain. 

Many  species  are  weeds  of  fields  and  gardens  ;  such  are  Smart  weed, 
and  Black  Bindweed  (Polygonum,  sp.),  Docks  and  Sorrel  (Rumex,  sp.). 

Order  Phytolaccaceee.— Mostly  tropical  herbs,  sometimes  shrubs 
or  tryes,  usually  with  several  free  or  united  carpels.  About  eighty 
ttyecies  are  known,  most  of  which  are  more  or  less  acrid. 

Phytolacca  decandra,  the  Common  Pokeweed,  is  our  most  notable 
representative.  It  is,  however,  a  doubtful  native. 

Order  Nyctaginacese.— Mostly  tropical  herbs,  shrubs,  or  trees  with 
opposite  leaves  and  tumid  joints  ;  flowers  gamophyllous.  About 
200  species  are  known.  The  roots  of  many  of  the  species  are  purgative 
or  emetic. 

Abronia,  of  several  species.  MiraMlis,  sp.,  the  Four  O'clock,  or 
Marvel  of  Peru,  and  some  others,  are  cultivated  as  ornaments. 

II.  G  AM  OPETAL^E.— Plants  whoso  flowers  generally 
have  both  sepals  and  petals,  the  latter  connately  united. 

580.— Cohort  XTT.  Lamiales.  Plants  with  zygomorphic 
flowers,  superior  ovaries,  indehiscent  fruits,  with  the  seeds 
solitary  in  the  two  to  four  cells. 

Order  Labiatae. — The  Mint  Family.  Aromatic  herbs  or  shrubs, 
with  four-angled  stems  and  opposite  leaves.  The  species,  of  which 
there  are  about  2500,  are  abundant  in  temperate  and  warm  climates, 
but  are  rare  in  cool  regions.  We  have  about  200  native  species  in 
North  America.  (Figs.  416-18.) 

Considering  the  size  of  the  order,  it  ranks  low  from  an  economic 
standpoint.  The  aromatic  herbage  has  led  to  the  use  of  many  species 
as  domestic  remedies,  few  of  which,  however,  are  really  valuable. 
Nevertheless,  there  are  many  species  yielding  minor  products  which 
are  of  some  value. 

Hyssopus  offlcinalis,  Hyssop,  a  small  shrub  of  Southern  Europe,  is 
commonly  cultivated  in  gardens  as  a  domestic  medicine. 

Hedeoma  pulegioides,  American  Pennyroyal,  is  an  c.fficinal  herb. 

Lavandula  vera,  Lavender,  is  a  shrubby  plant  of  the  South  of 
Europe,  cultivated  in  gardens,  and  used  as  a  domestic  perfume.  Oil 
of  Lavender  is  obtained  from  it  by  distillation. 

MentJia  .piperita,  Peppermint,  introduced  from  Europe,  yields  Oil 
of  Peppermint  by  distillation.  It  is  extensively  grown  in  Southern 
Michigan  and  New  York. 

Marrubium  vulgare,  White  Horehound,  of  Europe,  is  commonly 
found  in  gardens;  its  dried  herbage  is  officinal. 

Rosmarinus  ojftcinalis.  Rosemary,  T/iymns  vulgaris.  Thyme,  and  Sal- 


498 


SOT  A  NT. 


via  officinalis.  Garden  Sajre,  are  small  South  European  shrubs,  now 
to  be  found  in  all  gardens. 

Catnip,  Balm,  Horsemint,  and  many  others  are  used  more  or  less  as 
family  medicines,  for  which  purpose  tliey  are  well  suited,  being  harm- 
less and  feebly  operative. 

Several  tropical  species  of  Salvia  are  grown  as  ornaments,  as  are  also 
Golem  and  Peritta,  from  Southeastern  Asia. 

Order  Verbenaceee.— The  Vervain  Family.  Herbs,  shrubs,  <fr 
trees,  usually  not  aromatic,  with  mostly  four-angled  stems.  The 
species  number  about  700,  and  are  chiefly  tropical.  They  generally 
possess  a  bitter  and  astringent  principle. 

With  us  the  order  is  esteemed  principally  for  its  ornamental  value. 

FIGS.  416-18. — ILLUSTRATIONS  OF  LABIATE. 


Fig.  416.— Flower  of  Lqmium,  side  view. 

Pjg.  417. — Vertical  section  of  flower.    Magnified. 

Fig.  418.— Diiigram  ol  flower. 

Besides  the  several  South  American  species  of  Verbena  in  common  cul- 
tivation, the  so-called  Lemon  Verbena  (Lippia  citroidora)  from  Chili, 
and  the  species  of  Lantana  from  tropical    America,  there   are  to  be 
found  in  conservatories  many  showy  species  of  Clerodendron,from  Asia. 
/    Tectona  gramlis,  the  Teak  Tree  of  India,  is  a  gigantic  tree  whose 
(  yellowish  durable  wood  is  much  used  in  ship-building.     It  is  said  to 
\resist  the  attacks  of  Limnoria  terebrans  when  exposed  in  sea-water. 

Vittx  littoralis,  of  New  Zealand,  and  other  species,  growing  in  the 
Indo- Australian  region,  are  large  and  valuable  timber  trees. 
Order  Myoporinese. — Mostly  Anstralian  shrubs,  of  no  value. 
581.— Cohort  XHI.  Personales.      Plants  with   zygomor- 
phic   flowers,  superior  ovaries,  and  dehiscent  many-seeded 
fruits. 


PBR9ONALB8. 


499 


Order  Acanthaceee. — The  Acanthus  Family.  Herbs,  mostly  of 
the  tropics,  numbering  about  1500  species.  Thirty-five  or  forty  species 
occur  in  North  America,  mostly,  however,  in  the  South  and  West. 
Some  of  the  exotic  species  are  grown  in  conservatories,  e.g.,  Jasticia, 
Thuribergia,  etc. 

Order  Pedaliaceee.— Herbs  with  glandular  hairs.  The  most  im- 
portant species  are  the  Asiatic  Sesamum  Indicum  and  S.  orientule, 
whose  seeds  yield  an  oil  much  used  as  food  by  the  inhabitants  of  the 
tropics. 

Martynia  proboseidia,  the  Unicorn  Plant  of  the  Southwestern  United 
States,  is  notable  for  its  two-hooked  fruits. 

Order  Bignoniacese. — Mostly  woody  plants,  numbering  about  500 
species,  and  natives,  for  the  most  part,  of  the  tropics.  Many  are  cul- 

FIGS.  419-22.— ILLUSTRATIONS  OF  SCROPHULARIACILE  (Scrophularia,  sp.). 


4l».—  Flower.     Magmfit 
421.-Pistil.    Magnified 


Pig.  420.— Section  of  flower. 
Fig.  422.— Diagram  of  flower. 


tivated  for  their  fine  flowers  among  these  are  the  species  of  Bignonia,  ; 
Tecoma,  etc. 

Catalpa  bignonioides,  the  Common  Catalpa  of  the  Southern  United 
States,  is  a  fine  tree  for  shade  and  ornament.  Its  wood  is  said  to  be 
very  durable.  C.  speciosa  is  much  hardier  than  the  preceding. 

Crexcentia  Ciijete,  the  Calabash  Tree  of  tropical  America,  produces  a") 
large  pulpy  fruit  whose  hard  rind  is  used  as  a  water-vessel. 

Order  Gesneracese.— Mostly  tropical  plants,  represented  by  Achi- 
menes,  Gloxinia,  Gesnera,  etc.,  cultivated  in  conservatories. 

Order  Columelliaceae. — Evergreen  trees  or  shrubs  of  tropical 
America. 

Order  Lentibulariacece.  —  The  Bladderwort  Family.  Mostly 
aquatic  or  marsh  plants,  of  temperate  and  cold  regions,  interestinjr  on 
account  of  the  insect  catching  bladders  of  ihe  aquatic  species.  (For 


500  BOTANY. 

the  particulars  as  to  Pinguieula,  see  Darwin's  "Insectivorous  Plants," 
pp.  368-394,  and  for  Utriculana,  pp.  395-444.) 

Order  Orobanchaceee.  —  Leafless  parasitic  herbs,  numbering  150 
species,  widely  distributed.  We  have  about  a  dozen  native  species  in 
the  United  States. 

Order  Scrophulariaceae.— The  Figwort  Family.  Herbs  or  shrubs, 
rarely  trees,  with  two-celled  ovaries  and  central  placentae.  The 
species,  of  which  there  are  about  2000,  are  found  in  all  parts  of  the 
world,  extending  in  both  hemispheres  to  the  limits  of  vegetation. 
Many  of  the  species  contain  an  acrid  poisonous  principle.  (Figs.  419-22. ) 

Digitalis  purpurea,  the  Foxglove,  a  small  plant  of  Europe,  affords 
the  drug  Digitalis,  which  is  officinal. 

Many  species  are  cultivated  for  their  fine  flowers  ;  among  these  are 
the  Snapdragon  (Antirrhinum),  Monkey  Flower  (Mimulus),  Mauran- 
dia,  Pentstemon,  Veronica,,  Calceolaria,  etc. ,  etc. 

Paulownia  imperialis,  a  small  tree  of  Japan,  is  planted  in  the 
Southern  States. 

Verbascum  Thapsus,  the  Common  Mullein,  is  a  weed  introduced  from 
Europe. 

582.— Cohort  XIV.  Polemoniales.  Plants  with  alter- 
nate leaves,  regular  flowers,  stamens  isomerous  with  the 
corolla  lobes,  and  ovary  superior. 

Order  Solanaceee.— The  Nightshade  Family.  Herbaceous  or  woody 
plants  with  a  watery  juice  ;  ovary  two-celled,  many  ovuled.  This 
large  order  of  from  1200  to  1500  species,  which  are  chiefly  tropical,  is 
pervaded  by  a  more  or  less  poisonous  principle.  (Figs.  423-7.) 

There  are,  however,  a  few  valuable  food  plants. 

/  Solanum  tuberosum,  the  Potato,  is  a  native  of  America  from  Mexico 

/to  Chili,  and  a  variety  of  it  (var.  boreale)  even  occurs  in  New  Mexico. 

/   The  potato  was  introduced  into  Spain  in  the  early  part  of  the  sixteenth 

I     century,  and   into  England  by  Sir  Walter  Raleigh  in   1586,  but  for 

I     nearly  a  century  from  the  latter  date  it  was  little  used.     It  is  now, 

\    however,  grown  extensively  in  nearly  all  countries.       In  its  wild  state 

\its  tubers  are  not  more  than  two  to  three  centimetres  in  diameter,  but 

by  culture  and  selection  they  have  been  increased  fifteen  to  twenty 

times  in  bulk. 

Solanum  Melongena,  the  Egg  Plant,  of  South  America,  is  now  grown 
with  us  for  its  egg-shaped  edible  fruits. 

Ly coper sicumeiiculentum,  the  Tomato,  of  South  America,  is  grown 
On  most  warm  and  temperate  countries  for  its  wholesome  fruits. 

Physalis  Alkikengi,  the  Winter  Cherry  or  Strawberry  Tomato,  of 
the  South  of  Europe,  is  grown  in  our  gardens  for  its  edible  fruit,  which 
is  enclosed  in  the  inflated  calyx.  Our  native  species  of  this  genus 
called  commonly  Ground  Cherries,  are  valuable  for  food. 


POLEMONIALES. 


501 


"apsicum  annunm,  of  South  America,  and  other  species  of  the  genus, 
FIGS.  423-7.— ILLUSTRATIONS  OF  SOLANAOM:. 


Fig.  423.— Flowering  stem  of  Potato 

Fig.  424.— Flower  of  Bittersweet.     Magnified. 

Fig.  -425.— Diagram  of  Potato  flower. 

Fig  4dfi.— Calyx  and  pistil  of  Potato.    Magnified 

Fig.  427.-Sect.ion  of  seed  of  Bittersweet.     Magnified. 

bear    exceedingly  pungent    pods,   known  as  Peppers, 
pods  constitute  the  Cayenne  Pepper  of  commerce. 


FIG.  426. 


The    ground 


502  BOTANY. 

Atropa  Belladonna,  the  Deadly  Nightshade,  Hyoscynrmts  niger, 
Henbane,  and  Datura  Stramonium,  the  Thorn  Apple,  all  of  the  Old 
World,  supplj  powerful  narcotic  medicines.  That  from  the  first,  un- 
der the  name  of  Belladonna,  is  much  used  by  oculists  to  dilate  the  pu- 
pil of  the  eye. 

Nicotiana  Tabacum,  Tobacco,  a  South  American  herb,  was  cultivated 
by  the  American  aborigines  long  before  the  advent  of  Europeans.  It 
was  taken  to  Spain  about  the  beginning  of  the  sixteenth  century,  and 
to  England  from  sixty  to  eighty  years  later.  It  is  now  extensively 
cultivated  in  many  countries,  especially  in  the  United  States,  and  is 
used  by  all  the  civilized  nations  of  the  globe.  Two  or  three  other 
species  are  also  cultivated  in  different  parts  of  the  world. 

Among  the  ornamental  plants  of  the  order  are  species  of  Oestrum  and 
Datura,  from  South  America  and  Mexico  ;  Lycium,  from  Europe ; 
Petunia,,  from  South  America,  etc.,  etc. 

The  Thorn  Apple  mentioned  above,  and  the  Black  Nightshade  (So- 
lanum  nigrum)  are  common  as  weeds.  The  little  black  berries  of  the 
latter  are  made  into  pies  and  other  pastry  in  the  Mississippi  Valley. 

Order  Con  volvulaceee.— Herbaceous  (limbers,  rarely  shrubs,  often 
with  a  milky  juice;  ovary  of  1-5  cells,  each  2-,  rarely  1-4,  ovuled. 
About  800  species  are  known,  distributed  mostly  in  tropical  and  warm 
temperate  regions.  They  generally  possess  an  acrid  principle. 

The  Common  Morning-Glory  (fpomcea  purpurea)  and  one  or  two  near 
relatives,  all  from  tropical  America,  are  familiar  ornamental  climbers. 
/  Ipomcea  Batatas,  the  Sweet  Potato  of  India,  has  long  been  cultivated 
(  in  many  warm  and  temperate  climates  for  its  nutritious  roots. 

The  purgative  drug  Jalap  is  derived  from  the  root  of  a  Mexican 
plant  Ipomcea  purga. 

Convolvulus  Scammonia,  of  Western  Asia,  yields  the  drug  Scammony, 
and  from  the  wood  of  C.  Scoparius,  a  shrubby  species  of  the  Canary 
Islands,  Oil  of  Rhodium  is  extracted. 

C'uscuta,  the  parasitic  Dodder,  includes  many  species. 

Order  Borraginaceee. — The  Borage  Family.  Usually  hispid  herbs, 
shrubs,  or  trees,  with  a  four-parted  ovary,  each  part  one-ovuled.  The 
1200  'species  are  distributed  throughout  the  world,  although  they  are 
most  numerous  in  Southern  Europe  and  Western  and  Central  Asia. 
Many  of  the  species  possess  a  mucilaginous  property  useful  in  making 
cooling  drinks,  and  the  roots  of  some  contain  purple  or  brown  dyes. 

Anchusa  tinctoria,  of  the  South  of  Europe,  is  grown  in  France  and 
Germany  for  its  roots,  which  yield  the  red  dye  called  Alkanet. 

Among  the  commonly  cultivated  ornamental  plants  may  be  men- 
tioned the  Forget-me-not  (Myosotis  palustris)  of  Europe  and  the  Helio- 
trope (Heliotropium  Peruvianum)  of  Peru.  There  are  several  native 
and  introduced  species  which  are  vile  weeds. 

Order  Hydrophyllaceae.— A  small  order  of  mostly  American  herbs, 
closely  related  to  the  preceding. 


„ 


QENTIANALES.  •  503 

Species  of  NemopUla,  Phacelia,  Whitlavia,  etc.,  are  cultivated  in 
flower  gardens. 

Order  Polemoniaceee. — Mostly  herbs  of  North  America  and  North- 
ern Asia,  numbering  about  150  species. 

Species  of  Phlox,  Gilia,  Poltmonium,  Cobcea,  etc.,  are  cultivated  in 
flower  gardens. 

583.— Cohort  XV.  Gentianales.  Plants  with  opposite 
leaves,  regular  flowers,  superior  ovary,  and  the  stamens  usu- 
ally as  many  as  the  corolla  lobes  and  alternate  with  them. 

Order  Gentianaceee. — The  Gentian  Family.  Annual  or  perennial 
herbs,  with  a  watery  juice ;  ovary  generally  one-celled,  with  many 
ovules.  The  species,  of  which  there  are  about  500,  are  found  mostly 
in  temperate  and  cold  climates.  They  possess  a  bitter  principle,  which 
has  been  employed  in  medicine.  We  have  many  very  pretty  wild 
species. 

Order  Loganiacese. — Woody  plants  almost  entirely  of  the  tropics, 
with  two-celled  ovaries.  About  350  species  are  known  ;  they  contain 
a  bitter  principle  which  is  often  exceedingly  poisonous. 

Strychnos  nux-vomica  is  a  small  tree  of  India,  bearing  an  orange-like 
fruit  containing  numerous  large  flattish  seeds  (2  cm.  in  diameter). 
These  seeds  constitute  the  poisonous  drug,  Nux  Vomica  ;  they  con- 
tain two  alkaloids  to  which  their  activity  is  due,  viz ,  Strychnia 
(Cai  Ha!,  N,  O2)  and  Brucia  (C23  H2«  Ns  O4  +  4  H2  O).  The  ordinary 
form  of  the  first  as  found  in  the  shops  is  a  Sulphate  of  Strychnia. 

8.  toxifera,  a  tree  of  the  northern  parts  of  South  America,  yields 
from  its  bark  and  young  wood  the  famous  poison  known  as  Curare, 
Urari,  Ourari,  Woorara,  etc. 

S.  Tieute,  a  Jav«nese  climber,  furnishes  the  virulent  Upas  Tieute 
or  Tjettek  with  which  the  natives  poison  their  arrows. 

Order  Asclepiadaceae. — The  Milkweed  Family.  Woody  or  herba- 
ceous plants,  with  a  milky  juice ;  ovaries  two,  distinct,  but  with  a 
single  common  stigma ;  pollen  agglutinated  into  masses  (pollinia). 
This  large  order  of  about  1300  species  is  chiefly  tropical,  being  abun- 
dantly represented  in  America,  Africa,  and  Asia.  The  milky  juice  con- 
tains Caoutchouc,  and  usually  acrid  and  poisonous  principles.  But  few 
of  the  species  are  of  sufficient  economic  importance  to  demand  notice. 
Many  have  a  local  reputation  as  domestic  medicines.  (Figs.  438-32.) 

Some  are  favorites  in  the  flower  garden  or  conservatory,  e  g.,  the  Wax 
Plant  of  India  (Hoya  carnosa),  species  of  Geropegia,  Stephanolis,  Peri- 
ploca,  etc.  The  South  African  Stapelias  resemble  Cacti,  being  fleshy 
and  leafless 

The  peculiar  structure  of  the  flowers  in  this  order  has  recently  been 
shown  to  be  for  the  purpose  of  securing  the  services  of  insects  in  the 
process  of  pollination. 


504 


BOTANY. 


Order  Apocynaceee.  —The  Dogbane  Family.  Woody  or  herba- 
ceous plants,  generally  with  a  milky  juice  ;  ovaries  two,  distinct  or  co- 
hering, the  style  always  single;  pollen  granular.  In  this  order  of 
about  900  species  there  is  very  generally  present  a  drastic  purgative  or 
poisonous  principle.  Most  of  the  species  are  tropical,  a  few  only  ex- 
tending into  temperate  climates. 

The  milky  j uice  of  several  species  produces  Caoutchouc  when  evapo- 
rated,   and      that 

FIGS.  438-82.— ILLUSTRATIONS  or  ASCLEPIAS.  from  a  few  species 

of  Couma,  Taber- 
ncemontana,  etc. , 
in  northern  South 
America  is  used 
for  food. 

Tanghinia  vene- 
nifera,  a  tree  of 
Madagascar,  pro- 
duces a  fruit 
whose  seed  is  the 
exceedingly  viru- 
lent Ordeal  Poison 
or  Tanghin. 

Some  of  the 
trees  of  the  order 
furnish  timber, 
which  is  of  con- 
siderable local 
value. 

Our  native  spe- 
cies of  Apocynum 
(viz.,  A.  cannahin- 
um  and  A.  andro- 
scemifoliuiri)  pos- 
sess a  tough  fib- 
rous bark  which 
was  used  by  the 
Indians  for  mak- 
ing cordage,  nets, 
etc. 

Among  the  cul- 
tivated plants  are  Nerium  Oleander,  the  Oleander  from  the  Levant, 
an  evergreen  shrub  or  small  tree  with  poisonous  wood,  bark  and  foli- 
age :  Vinca,  sp.  Periwinkle  or,  as  it  is  erroneously  called,  Trailing 
Myrtle  ;  Echites,  Attamanda,  etc. 

Order  Salvadoraceee. — A  few  shrubs  of  the  Old  World  tropics. 
Order  Oleacese.— The  Olive  Family.     Woody  or  rarely  herbaceous 


FIG.  431 


Magnified. 


Fig.  428.— Flowrr,  with  perianth  reflexed 
Fig.  429. -Stamen,  with  its  hood.    Magnified. 
Fig.  430.— Gynfficinm  with  pollen-masses  adheri 
tigma  ;  two  separated  pollen-masses  at  the  side.    " 
Fig.  431. — Diagram  of  flower. 
Fig.  432.— Seed.    Magnified. 


to  the 


EBENALES.  505 

plants  ovaries  two-celled,  each  cell  with  one  to  three  ovules  ;  stamens 
two.  The  species,  280  in  number,  are  distributed  widely  over  tem- 
perate and  tropical  regions. 

Olea  Ktiropcea,  the  Olive,  probably  a  native  of  Western  Asia,  is  now 
extensively  cultivated  in  all  warm  temperate  climates.  It  is  a  small 
evergreen  tree,  and  produces  a  bluish  oily  drupe,  from  which  by 
pressure  Olive  Oil  or  Sweet  Oil  is  obtained.  The  wood  of  the  Olive 
Tree  is  very  hard  and  is  used  in  turnery  and  cabinet-making. 

Fraxinus  excelsior,  the  Ash  Tree  of  Europe  and  North  Africa,  is  a 
large  tree,  yielding  a  white,  hard,  tough  and  elastic  timber,  highly 
prized  in  the  manufacture  of  implements,  in  turnery,  coach-making, 
etc.  The  tree  is  frequently  planted  in  the  United  States. 

F.  Americana,  The  American  White  Ash  of  the  Eastern  United 
States,  is  larger  than  the  preceding,  attaining  frequently  a  height  of 
thirty  metres  (100  feei)  or  more.  Its  timber  resembles  that  ol  the  Ash 
of  Europe,  but  is  even  more  valuable. 

F,  Oregana,.o{  Oregon  and  Northern  California,  furnishes  a  timber 
much  like  that  of  the  White  Ash. 

F.  sambucifolia,  the  Black  Ash  of  the  Northeastern  United  States, 
is  a  large  tree  usually  found  in  moist  situations  ;  the  annual  layers  of 
its  wood  easily  separate  into  thin  strips  admirably  suited  to  make  into 
barrel  hoops,  baskets,  etc.  Other  native  species  also  supply  more  or 
less  valuable  timber. 

In  Jamaica  a  species  of  Linociera  produces  a  very  hard, fragrant  and 
excellent  timber  known  as  Jamaica  Rosewood.  A  species  of  Notelcea, 
in  Australia  and  Tasmania,  yields  a  hard  timber  called  Iron- wood,  much 
used  in  making  ship-blocks,  and  for  other  purposes  where  hardness  is 
required.  Several  genera  afford  ornamental  plants,  e.g.,  Jasminum,  of 
many  species,  Jessamine  ;  Syringa,  the  Lilac;  Liffustrum,  the  Privet; 
Chionanthus,  the  Fringe  Tree  ;  Forsythia,  etc. 

584.— Cohort  XVI.  Ebenales.— Shrubs  or  trees  with  al- 
ternate leaves,  regular  flowers,  and  superior  ovary  ;  ovules 
usually  solitary  in  the  two  to  many  cells  ;  stamens  generally 
alternate  with  the  corolla  lobes. 

Order  Styracaceee.— Plants  with  a  watery  juice  and  mouoclinous 
flowers.  There  are  about  220  species  in  the  order,  found  almost  en- 
tirely in  the  tropical  parts  of  America,  Asia,  and  Australia. 

Styrax  ojficinale,  of  the  Levant,  yields  from  incisions  in  the  bark 
Gum  Storax,  and  from  S.  benzoin  of  the  Malay  Islands,  Gum  Benzoin  is 
similarly  obtained. 

A  few  species  afford  dyes,  but  none  are  widely  used. 

Halesia  te'raptera,  the  Silver-Bell  or  Snow-Drop  Tree  of  the  South- 
ern United  States,  is  a  highly  ornamental  shrub. 

Order  Ebenaceae.— The   Ebony  Family.      Plants   with  a  watery 


506  BOTANY. 

juice,  and  mostly  diclinous  flowers.  About  250  species  are  known  in 
this  order,  the  greater  part  occurring  within  the  tropics. 

Dioapyros  reticulata,  a  large  tree  of  the  island  of  Mauritius,  produces 
the  best  of  the  timber  known  as  Ebony.  Ebony  is  also  derived  from 
D.  Ebenum  and  D.  melanoxylon  of  Ceylon,  and  D.  Ebenaster  of  the 
Calcutta  region. 

D.  Jtirsuta,  of  Ceylon,  produces  the  beautiful  "  Calamander  Wood," 
which  is  variegated  with  brown  and  yellow  stripes. 

D.  Kaki,  a  Chinese  and  Japanese  tree,  bears  plum-like  fruits  which 
are  delicious.  In  our  markets  they  are  known  as  Chinese  Dates. 

D.  Virginiana,  the  Persimmon  of  the  Southern  United  States,  pro- 
duces fruits  similar  to  the  last,  but  astringent  and  inedible  until  after 
being  frosted.  Doubtless  under  culture  this  fruit  might  be  made  to 
equal  the  preceding. 

Order  Sapotacese. — Plants  with  a  milky  juice  and  monoclinous 
flowers.  A  tropical  order  of  about  300  species,  a  few  of  which  extend 
into  temperate  regions. 

Isonandra  gutta,  a  large  tree  of  the  Malay  Islands  and  Borneo,  is  the 
source  of  the  Gutta  Percha  of  commerce.  The  milky  juice  is  collected 
and  evaporated,  and  then  constitutes  the  crude  Gutta  Percha. 

Chrysophyllum  Cainito,  the  Star  Apple,  Archas  snpota,  the  Sapodilla 
Plum,  and  Archas  mammosa,  the  Marmalade,  are  West  Indian  trees, 
which  bear  delicious  pulpy  fruits. 

Bassia  butyracea  and  B.  iatifolia,  both  of  India,  and  B.  Parkii,  of 
tropical  Africa,  are  called  Butter  Trees,  on  account  of  the  butter-like 
fatty  substance  obtained  from  their  seeds  by  pressure. 

We  have  eight  species  within  the  United  States,  found  mostly  along 
our  Southern  coast.  Two  species  of  Bumelia  reach  the  Ohio  River. 

585.— Cohort  XVII.  Primulales.  —  Plants  with  mostly 
alternate  leaves,  regular  flowers,  and  superior  one-celled 
ovaries  ;  stamens  generally  opposite  to  the  corolla  lobes. 

Order  Myrsinacese. — Trees  or  shrubs,  mostly  of  the  tropics.  Three 
or  four  species  barely  reach  the  southern  part  of  Florida. 

Order  Primulaceee. — The  Primrose  Family.  Herbs  mostly  with 
radical  leaves  ;  placenta  central,  free  and  globose;  ovules  many,  fixed 
by  their  vcntial  face.  Species  250,  mostly  of  the  North  Temperate 
Zone.  (Figs.  433-5.) 

The  order  is  chiefly  valuable  for  its  ornamental  plants. 

Primula  tulgaris,  the  Primrose,  and  P.  veris,  the  Cowslip,  are  com- 
mon English  plants,  often  referred  to  in  poetry. 

P.  Sinensis,  the  Chinese  Primrose,  and  P.  Auricula,  the  Auricula 
from  Southern  Europe,  are  common  in  gardens  and  green-houses. 

Cyclamen,  Dodecatheon,  and  Lyfrimacliia  contain  fine  ornamental 
species. 


PRIMULALES. 


sor 


Anagattis  arvensis  is  a  little  weed  from  Europe. 

Order  Plantaginaceee.— The  Plantain  Family.  Herbs,  mostly  with 
radical  leaves  ;  placenta  central,  not  free  ;  ovules  usually  many,  fixed 
by  their  ventral  face.  This  anomalous  order  appears  to  be  more  at 
home  in  this  Cohort  than  anywhere  else.  It  disagrees  with  the  charac- 
ters given  for  the  Cohort  in  its  ovary  being  for  the  most  part  two-celled. 

FIGS.  433-5.— ILLUSTRATIONS  OF  ANAGALLIS  ARVENSIS. 


Pis.  433. 


PIG.  435. 


Fig.  433. — Section  of  young  flower-bud.  I,  calyx  ;  c,  corolla  ;  a,  stamens  ;  K,  pis- 
til ;  S,  placenta.  B.  gyncecium  further  advanced.  C,  gyncecium  ready  for  fertiliza- 
tion. D,  young  fruit.  (After  Sachs.) 

Fig.  434.— R  pe  fruit.     Magn  fled. 

Fig.  435.— Dehiscent  fruit.    Magnified,    g,  seeds. 

Otherwise  its  agreement  is  so  marked  as  to  allow  us  to  regard  it  as  a 
group  of  degraded  Primulales.  The  species  number  about  fifty,  and 
are  found  in  all  tempeiate  regions. 

Plantago  major,  the  common  Plantain,  is  found  everywhere  in  door- 
yards. 

Order  Plumbaginacese.—  Herbs  or  barely  woody  plants,  with 
leaves  radical  or  cauline  ;  ovary  one-celled,  one-ovuled.  About  200 
species  are  known,  distributed  throughout  temperate  climates. 


508 


BOTANY. 


Armeria  milgaris,  Thrift,  of  Europe,  is  cultivated  in  flower-gardens. 

Plumbago /  several  South  African  and  East  Indian  species,  are  to  be 
met  with  in  conservatories. 

586.— Cohort  XVHL  Ericales.  —  Plants  with  regular 
flowers,  and  superior  two  to  many-celled  ovaries  ;  stamens  as 
many  or  twice  as  many  as  the  corolla  lobes,  hypogynous  or 
epipetalous. 

Order  Lennoaceee.— Californian  and  Mexican  leafless  root-parasites. 

Order  Diapensiaceee.— Low  plants  (six  to  eight  species)  of  North 
America  and  Eastern  Asia,  of  much  botanical,  but  no  economic  interest. 

Order  Ericaceae.— The  Heath  Family.  Mostly  shrubs  or  small 
trees,  a  few  herbs,  with  usually  alternate,  simple,  and  entire  leaves  ; 
ovary  mostly  five-celled,  with  placentae  in  the  axis  ;  anthers  opening 
by  a  terminal  pore,  rarely  by  a  lateral  slit ;  pollen  grains  compound, 
rarely  simple. 

Under  these  characters  are  included  about  1700  species,  which  are 
often  regarded  as  constituting  five  orders,  viz.,  Ericineae,  Epacrideae, 
Pyrolineae,  Monotropeae,  and  Vaccinieae,  here  to  be  considered  as  sub- 
orders. While,  however,  there  are  considerable  differences  between 
the  plants  here  brought  together,  they  are  not  important  enough  to 
counterbalance  the  many  evident  resemblances.  The  relationship  sub- 
sisting between  the  sub-orders  may  be  shown  as  follows  : 

VACCINIE^. 

^1  (Ovary  inferior.) 


EPACRIDE^l  <- 

f  Stamens  epipetal-  ^| 
I  ous  or  hypogyn-  ! 
]  ous  ;  anthers) 
[with  a  si  it. 


-ERICINE^E- 
Qamopetalous ; 
ovary  superior  ; 
stamens  hypogyn- 
ous  ;  anthers 
with  a  pore  ;  pol- 
1  e  n  grains  com- 
pound. 


PYROLINE.E. 

(Choripetalous.) 


MONOTROPE^. 
<\  Choripetalous;  anthers  with  a) 
/  slit ;  pollen  grains  simple.       j 


ERIC  ALES. 


500 


The  Ericineae  are  doubtless  to  be  regarded  as  the  central  or  main 
group,  from  which  the  others  have  diverged.  In  the  diagram  the  dis- 
tinguishing characters  which  are  given  for  Ericineae  may  be  regarded 
as  typical  for  the  order,  and  under  each  of  the  other  sub-orders  are 
given  the  exceptional  characters,  or  more  properly,  the  modifi  nations  of 
the  original  ordinal  characters. 

Sub-Order  Ericinece. — About   1000  species  of  shrubs,  many 
evergreen.      Many  are       Fiog  436_9._lLLU8TBATIONg  OP  EBICA  C1NEBBA. 
of  great  beauty,  and  are  f .  , 

extensively  grown  as 
ornaments  ;  others  are 
good-sized  trees,  and 
furnish  valuable  tim- 
ber. (Figs.  436-9.) 

Arbutus  Menziesii, 
the  Madrona  of  the  Pa- 
cific coast  of  the  Unit- 
ed States,  is  an  ever- 
green tree  twenty-four 
to  thirty  metres  (80  to 
100  ft.)  in  height.  Its 
hard  wood  is  useful  in 
furniture-making. 

Arctostaphylos  pun- 
gens  and  A.  ylauca  are 
large  evergreen  shrubs 
of  California,  which 
bear  the  name  of  Man- 
zanita.  The  heavy, 
dark-colored,  and  fine- 
grained wood  is  used  in 
turnery  and  furniture- 
making.  The  berries 
are  eaten  by  grizzly 
bears. 

A.       Uva-ursi,     the 

Bearberry  of  the  colder      Fig.  438.— Diagram  of  flower, 
portions       of       North       *»*  *»-Sectton  of  ovary.    Magnified. 
America,  Europe,  and  Asia,  bears  bitter  and  astringent  leaves,  which 
are  officinal. 

Catluna  vulgaris,  the  Common  Heath  of  Central  and  Northern  Europe, 
is  a  low,  straggling  evergreen  under-shrub.  Its  stems  are  made  into 
brooms,  and  its  flowers  afford  an  abundance  of  excellent  honey.  It 
occurs  in  a  few  scattered  localities  in  Massachusetts,  Maine,  Nova 
Scotia,  and  northward,  but  it  is  doubtful  whether  it  is  really  indigenous 
to  any  part  of  the  United  States. 


FIG.  438.  FIG.  439. 

Flower 

Section  of  flower.    Magnified. 


Fig.  436.— Flowering  stem 
Fig.  437.--  6  - 


510  BOTANY. 

Epigcea  repens,  the  Mayflower  or  Trailing  Arbutus,  is  a  low  trailing 
plant  witli  a  woody  stem,  found  chiefly  in  New  England  and  adjacent 
rejrions.  Its  rose-colored  fragrant  flowers,  which  appear  in  early 
spring,  are  much,  sought  for. 

Erica.  This  large  genus,  including  400  or  more  species,  is  distrib- 
uted in  Europe,  Northern  Asia,  and  Northern  and  Southern  Africa, 
reaching  its  maximum  in  the  latter  region.  None  are  found  in 
America.  Many  species  are  grown  in  conservatories. 

Oaultheria  procumbens,  Wintergreen  or  Checkerberry,  has  aromatic 
fruit  and  foliage.  From  the  latter  an  officinal  oil  is  distilled. 

Kalmia.  A  genus  of  beautiful  plants  with  curious  flowers  ;  each 
stamen  when  the  flower  opens  is  bent  backward,  and  its  anther  is 
hidden  in  a  sac  in  the  corolla  ;  somewhat  later  the  anthers  escape  from 
the  sacs  and  the  pollen  is  ejected.  This  mechanism  has  probably  to 
do  with  the  process  of  cross-fertilization  through  the  agency  of  insects. 
Some  of  our  native  species  are  reputed  to  be  poisonous  to  domestic 
animals,  e.g.,  K.  angmtifolia,  the  Sheep  Laurel  or  Lambkill. 

Rhododendron.  This  genus  is  now  made  to  include  the  Azaleas  as 
well  as  the  true  Rhododendrons.  Some  species  become  lar<ie  trees  (R. 
tirboreum  of  the  Himalayas),  while  many  are  highly  prized  as  orna- 
mental shrubs.  The  Great  Laurel  (R.  maximum),  &  shrub  or  small  tree, 
with  large  evergreen  leathery  leaves,  grows  in  the  Alleghany  Moun- 
tains. R.  Cataicbiense  and  its  hybrids  with  R.  arboreum  are  extensive- 
ly planted  for  ornaments.  R.  Indica  is  the  Azalea  of  the  florists  ;  it 
has  many  varieties. 

Sub-Order  Epacridece. — About  320  species  of  shrubs  or  small 
trees,  often  with  a  Heath-like  appearance  ;  natives  of  Australia  and 
many  of  the  Pacific  islands  ;  only  one  species  is  found  in  South  Amer- 
ica. Many  species  are  grown  in  conservatories,  e.g.,  Epacris,  Leucopo- 
gon,  DracophyUum,  etc. 

Sub-Order  fyrolinece.—Perenni&l  herbs,  about  twenty  species, 
all  of  the  North  Temperate  Zone.  They  are  of  but  little  account 
economically  or  otherwise.  Chimaphtta  maculata,  Pipsissewa  or 
Prince's  Pine,  was  used  by  the  Indians  as  a  medicine.  The  dried 
leaves  constitute  the  officinal  drug  Chiinaphila. 

The  anomalous  genus  Clethra,  including  twenty-five  species  of  shrubs 
and  trees  (American  and  Asiatic)  is  sometimes  placed  in  this  sub-order 
on  account  of  its  choripetalous  corolla;  it  appears,  however,  to  prop- 
erly fall  into  the  Ericinese,  in  either  the  tribe  Andromedese  or  Rho- 
doreae. 

Sub-Order  JHonotropete. — Small  herbs,  parasitic  or  sapro- 
phytic,  destitute  of  chlorophyll ;  their  leaves  are  reduced  to  mere 
bracts,  and  their  flowers  and  seeds  show  still  further  degradation.  Ten 
or  twelve  species  are  known,  distributed  throughout  the  temperate 
parts  of  the  Northern  Hemisphere. 


CAMPANALES. 


511 


FIGS.  440-41.— ILLUSTRATIONS  OF  VACCINIUM  MTR- 
TILLUS. 


Monotropa  unifiora,  Indian  Pipe,  is  common  throughout  nearly  all 
North  America.  It  appears  to  be  saprophytic. 

Barcodes  sanguinea  is  the  interesting  Snow  Plant,  which  in  the 
Sierra  Nevada  Mountains  of  California  shoots  up  its  flesh-red  stem 
and  flowers  in  early  spring,  soon  after  the  snow  melts. 

Sub-Oi'der  Vacciniece. — Shrubby  plants,  mostly  of  the  North- 
ern Hemisphere.  Species,  320.  The  thick  adherent  calyx-tube  of  the 
flower  often  becomes  fleshy  and  edilile  in  fruit.  (Figs.  440-41.) 

Oaylussacia  >esinosa,  a  low  shrub  of  the  Eastern  United  States,  pro- 
duces the  Black  Huckleberries  of  the  markets. 

Vaccinium  Pennsyhanicum,  the  Early  Blueberry,  or  Blue  Huckle- 
berry, and  V.  vacillans,  the  Low  or  Late  Blueberry,  are  common  in  the 
Northeastern  United  States. 

V.  corymbosum,  the  Swamp  Blueberry,  is  also  common  in  the  Eastern 
United  States.  Be- 
sides these,  other  spe- 
cies furnish  edible 
fruits  which  are  some- 
times found  in  the  mar- 
kets. V.  MyrtiUus  oc- 
curs with  us  only  in  the 
Rocky  and  Sierra  Ne- 
vada Mountains. 

V.  Oxycoccus,  the 
Small  Cranberry  of  the 
Northeastern  United 
States,  and  the  much 
larger  var.  macrocar- 
pon,  or  Large  Cran- 
berry, which  extends 
much  further  south, 

are  valuable  for  their  acid  fruits.     The  variety  is  extensively  culti- 
vated from  Massachusetts  to  Wisconsin. 

587.— Cohort  XIX.  Campanales.  Plants  with  flowers 
mostly  zygomorphic  ;  ovary  inferior,  two-  to  six-celled  (rarely 
one-celled)  ;  ovules  usually  many  in  each  cell. 

Order  Campanulacege.— Herbs,  rarely  shrubs,  usually  with  alter- 
nate leaves  and  a  milky  juice;  ovary  two-  to  many-celled.  The  1000 
species  which  compose  this  order  were  until  recently  divided  between 
the  two  orders  Lobeliaceae  and  Campanulacea),  which  are  here  merged 
into  one.  The  order  as  now  constituted  is  represented  in  all  regions, 
but  most  abundantly  in  temperate  ones.  All  possess  more  or  less 
acridity,  which  in  some  cases  becomes  a  dangerous  poison. 

Lobelia  inflata  and  L.  xyphilitica  of  the  Eastern  United  States  have 
been  used  in  medicine  ;  now  principally  used  by  quacks, 


FIG.  441. 


Fig.  440.- Flower.    Magnified. 

Fig.  441. -Section  ol  flower.    Magnified. 


512  BOTANY. 

L.  cardinal!*,  the  Cardinal  Flower,  of  the  Eastern  United  States 
and  several  foreign  species,  are  showy  plants  in  the  flower-garden. 

Campanula  medium,  Canterbury  Bells,  and  other  European  species 
are  in  common  cultivation. 

Order  Goodeniaceae.— Mostly  Australian,  herbaceous  plants,  num- 
bering about  200  species,  of  but  little  economic  value. 

Order  Stylidiaceee.— Curious  herbs,  about  100  in  number,  mostly 
Australian.  Species  of  Stylidium  are  grown  in  const- rvatories. 

588.— Cohort  XX.  Asterales.  Plants  with  actinomorphic 
or  zygomorphic  flowers  ;  stamens  inserted  on  the  corolla  and 
isomerous  with  its  lobes  ;  ovary  inferior,  one-celled,  one- 
ovuled  (rarely  two-  to  three-celled).  Calyx  limb  often  greatly 
reduced,  forming  a  pappus,  sometimes  wanting. 

Order  Composites.— The  Sunflower  Family.  Herbs,  shrubs,  or 
rarely  trees  ;  anthers  united  to  each  other ;  ovary,  one-celled,  contain- 
ing a  single  erect  seed  destitute  of  endosperm.  In  this  immense 
family  of  fully  10,000  species,  distributed  throughout  all  parts  of  the 
world,  the  small  flowers  are  gathered  into  compact  heads,  which  them- 
selves often  resemble  single  flowers.  Many  of  the  species  are  of  great 
beauty,  and  are  greatly  admired  as  ornaments,  but  it  is  curious  to 
observe,  that  despite  the  great  size  of  the  order,  there  are  but  few 
plants  which  are  otherwise  of  any  considerable  use  to  man.  Many  are 
troublesome  weeds. 

In  Bentham  and  Hooker's  "  Genera  Plantarum,"  the  766  genera  are 
arranged  under  thirteen  tribes,  as  given  below. 

Tribe   1.     Cichoriacece.—  Flowers  all  ligulate  ;   juice  milky. 

Cichorium  Inlybus,  Chicory,  of  Europe,  is  much  cultivated  in  France 
and  Germany.  Its  r«.ots  are  used  to  adulterate  coffee.  C.  Endivia,  of 
India,  is  the  Endive,  cultivated  in  gardens  as  a  salad  plant. 

Lactuca  satira,  the  Garden  Lettuce,  is  probably  a  native  of  Asia. 
The  dried  juice  of  L.  virosa,  of  Europe,  constitutes  the  narcotic  drug 
Lactuca  riuin. 

Taraxacum  Dens-leonis,  the  Common  Dandelion,  is  used  somewhat 
in  medicine.  (Figs.  442-5.) 

Tragopogon  porrifolius,  Salsify,  of  Europe,  is  cultivated  for  its 
edible  root. 

Tribe  2.  Mwtisiacea'. — Flowers  usually  bifid,  i.e.,  two-lipped. 
We  have  but  one  representative,  CkoftaKa  tomentosa,  in  Southeastern 
United  States.  They  abound  in  tropical  America. 

Tribe  3.    Cynaroidece.— Flowers  all  tubular. 
Cynara  Scolymus,  a  native  of  the  Mediterranean  basin,  is  the  Arti- 
choke, gro\vn  for  the  thick  scales  of  its  flower  heads,  which  are  edible. 
Carthamus  tinctoria,  a  Chinese  annual,  is  grown  in  gardens  for  its 


A8T&RALES. 


513 


red  flowers,  which  are  gathered  and  dried,  constituting  the  dye  Saf- 
flower. 

Centaurea  odoratu  and  C.  moschata,  from  Asia,  and  other  European 
and  American  species,  are  cultivated  in  flower  gardens. 

Cnicus  includes  our  Thistles,  most  of   which  are   weeds  in  fields. 


FIGS   442  5.— ILLUSTRATIONS  OF  TARAXACUM  DBNS-LEONIS. 


FIG.  442. 


FIG.  443. 


Fie.  445. 

ting  head  on  the 


Fig.  442.— Head  of  flowers,  with  a  bud  on  the  right,  a  closed  f 
left,  and  two  leaves. 
Eig.  443.— Flower     Magnified.  Fig.  444.— Receptacle  and  fruits. 

Fig.  445 —Fruit.    Magnified. 

C.  arvensis,  the  so  called  Canada  Thistle,  is  in  reality  an  Old  World 
species.  It  is  one  of  the  most  difficult  of  all  our  weeds  to  eradicate  on 
account  of  its  underground  stems,  which  are  tenacious  of  life. 
C'.  lanceolatus,  the  Common  Tiiistle,  is  another  introduced  speciea. 


514  BOTANY. 

C.  pumilus,  the  Pasture  Thistle,  and  C.  horridulus,  the  Yellow  Thistle, 
are  indigenous. 

Tribe  4.  Arctotidece.— Flowers  partly  tubular  (forming  a  central 
disk),  and  partly  ligulate  (forming  rays  to  the  head).  Natives  of 
Africa  and  Australia. 

Tribe  5.  Calendulftcere.— Similar  to  the  preceding.  Natives 
mostly  of  Africa  and  Asia. 

Tribe  6'.  S'necionitlew.— Heads  mostly  with  disk  and  ray  flow, 
ers. 

Arnica  montana,  a  perennial  of  Europe  and  Siberia,  from  which  the 
officinal  Arnica  flowers  and  routs  are  derived. 

Senecio  scandens,  of  the  Cape  of  Good  Hope,  is  cultivated  as  a  house 
plant  under  the  name  of  German  Ivy. 

Many  other  species  of  this  genus  are  cultivated — e.g. ,  the  so-called 
Cinerarias,  Cacalia,  Farfugium,  etc.  Some  of  the  species  are  common 
weeds. 

Bedfordia  salicina,  a  native  of  Tasmania,  attains  a  height  of  four  to 
five  metres  (15  ft.).  Its  wood  is  hard,  and  is  much  prized  for  cabinet 
work  on  account  of  its  beautiful  grain. 

Tribe  7.  Anthemidece.—Re&ds  mostly  with  disk  and  ray  flow- 
ers. 

Artemisia  Absintldum,  the  Common  Wormwood  of  Europe,  is  cul- 
tivated in  old  gardens  as  a  domestic  remedy.  In  Europe  an  alcoholic 
extract  called  Absiuthe  is  u-ed  as  an  intoxicating  beverage.  Some 
species  in  the  Rocky  Mountain  region  are  tall  shrubs,  and  are  called 
Sage  Brush.  They  furnish  a  valuable  fuel. 

Anthemis  ?iol>ilis,  Chamomile,  and  Tanacetum  vulgare.  Tansy,  of 
Europe,  are  well  known  domestic  herbs. 

Chrysanthemum  roseitm,  from  Persia,  C.  Indicnm,  from  China,  and 
C.  coronarium,  from  North  Africa,  are  the  originals  of  the  Chrysanthe- 
mums so  common  in  flower-gardens. 

C.  Leucaidhemum,  the  Ox  Eye  Daisy,  is  a  most  difficult  weed  to  eradi- 
cate. 

Tribe  8.  Helen  ioidetr. — Heads  mostly  with  disk  and  ray  flowers. 

To  this  belong  the  so-called  French  or  African  Marigolds,  Tagetes,  of 
several  species,  cultivated  in  flower  gardens.  They  are  in  reality  na- 
tives of  tropical  America. 

Tribe  9.  HeliaHthoidece.—tte&ds  mostly  with  disk  and  ray 
flowers. 

Dahlia  variabilis  and  one  or  two  other  species  from  Mexico,  are  the 
original  forms  of  the  Dahlias  of  the  flower-gardens. 

Zinnia  elegans,  of  Mexico,  is  the  well  known  Zinnia  of  the  gardens. 

Coreopsis,  of  several  Arkansas  and  Texas  species,  are  grown  under 
the  name  of  Calliopsis. 

Helianthns  annuns,  the  Common  Sunflower,  is  a  native  of  the  Texan 
and  Mexican  regions.  Aside  from  its  ornamental  use,  its  oily  seeds  are 


ASTER  ALES. 


515 


valuable  for  fattening  poultry,  and  the  dried  stems  are  good  for  fuel, 
hi  Russia  a  valuable  oil  is  obtained  from  the  seeds. 

//.  tuberosus,  the  so-called  Jerusalem  or  Brazilian  Artichoke,  is 
much  growu  for  its  potato-like  tubers,  which  are  fed  to  cattle  and  swine. 
It  is  probably  derived  from  H.  doronicoides,  of  the  Mississippi  Valley, 
by  long  cultivation.  The  name  "Jerusalem  "  Artichoke  is  a  corruption 
of  the  Italian  "Girasoki — i.e.,  sunflower. 

Among  the  weeds  are  the  Ragweeds  (Ambrosia),  Cockleburs  (Xan- 
thium),  Spanish  Needles  (Bidens). 

Silphium  laciniatum  is  the  Compass  Plant  of  the  Mississippi  Valley. 

PIGS.  446-50. — ILLUSTRATIONS  OF  EUPATORIUK. 


PIG.  447.  FIG.  448. 

Fig.  446.— Head  of  flowers. 
Fig.  448. -Flower.    Magnified. 
Fig.  450.— Pistil.    Magnified. 


FIG.  449. 


FIG.  450. 


Fig.  447.— Diagram  of  flower. 

Fig.  449.— Section  of  flower.    Magnified. 


Its  large  erect  pinnately  lobed  leaves  twist  upon  their  petioles  so  as  to 
present  one  surface  of  the  blade  to  the  east  and  the  other  to  the  west, 
the  two  edges  being  upon  the  meridian.  (Fig.  134,  p.  157.) 

Tribe  1O.  Imiloidfce.—He&As  mostly  with  disk  and  ray  flowers. 

Helipterum  Manglem,  of  Australia,  is  one  of  the  "  Everlasting  flow- 
ers," cultivated  under  the  namo  of  Rhodanthe,  and  used  for  winter 
bouquets. 


516  BOTANY. 

Hdichrysum,  sp.,  is  also  cultivated  for  tlie  same  purpose. 

Inula  Heleitium,  Elecampane,  of  Europe,  is  cultivated  in  gardens  for 
its  medicinal  root. 

Tribe  11.  Asteroidece.—Re&ds  mostly  with  disk  and  ray  flowers. 

Aside  from  our  native  species  of  As'.er  and  Solidago  (Golden  Rods), 
which  are  ornamental,  Belli*  per ennte,  the  English  Daisy,  and  Callis 
tephus  Chinensin,  the  China  Aster,  are  common  in  flower-gardens. 

Grindelia  robusta  and  other  species  are  important  as  furnishing  in 
the  alcoholic  infusion  of  their  leaves  a  cure  for  the  poisoning  by  Poison 
Ivy. 

Olearia  argophylla,  the  Musk  Tree  of  Tasmania,  attains  a  height  of 
six  metres  (20  ft.)  and  a  diameter  of  thirty  cm.  (1  ft.).  Its  wood  is  hard, 
and  is  used  in  turnery  and  in  the  manufacture  of  agricultural  imple- 
ments. 

0.  furfuracea  and  several  other  New  Zealand  species  are  equally 
valuable. 

Tribe  12.  Eupatoriacece.— Flowers  all  tubular.  (Figs.  446-50 ) 

Species  of  Eupatorium  are  used  as  domestic  medicines.  Several  of 
the  species  are  ornamental. 

Mikania  scandens,  a  native  climber,  is  cultivated  for  ornament. 

The  native  species  of  Liatris,  Blazing  Star,  are  also  quite  orna- 
mental. 

Tribe  13.    Vernoniacece.— Flowers  all  tubular. 

The  species  of  Vernonia,  known  by  the  name  of  Iron-weed,  are  com- 
mon weeds  on  low  grounds. 

Order  Calyceraceee.— A  few  South  American  herbs  resembling 
Compositse,  but  with  the  ovule  pendulous. 

Order  Dipsacese. — Herbs,  with  distinct  anthers  and  pendulous 
seeds,  which  contain  endosperm.  Species  one  hundred  and  twenty, 
mostly  of  the  North  Temperate  Zone. 

Dipsaeus  Futtonum,  Fuller's  Teasel,  of  Europe,  is  jrrown  for  its  hard- 
bracted  ripe  heads,  which  are  used  by  fullers  in  dressing  woolen  cloth. 

Scabiosa  contains  many  ornamental  species. 

Order  Valerianaceee. — Herbs,  with  distinct  anthers,  and  three- 
celled,  but  (by  absorption)  one-seeded  ovary  ;  seed  without  endosperm. 
Species  about  three  hundred,  mostly  of  the  North  Temperate  Zone. 

Valeriana  officinnlis,  of  Europe,  has  a  thickish  root,  which,  in  the 
dried  state,  is  the  officinal  Viilerian. 

589.— Cohort  XXI.  Rubiales.  Plants  with  actinomorph- 
ic  or  zygomorphic  flowers  ;  stamens  inserted  on  the  corollii 
and  isomerous  with  its  lobes  ;  ovary  inferior,  two-  to  many- 
celled,  each  cell  with  one  to  many  ovules.  Calyx  never 
pappose. 

Order  Rubiaceee.— Herbs,  shrubs,  and  trees  ;  flowers  generally  rejr. 


RUB  TALES. 


517 


ular  (actinomorphic) ;  leaves  with  stipules.  A  large  order  of  over  4000 
species,  the  greater  part  of  which  inhabit  tropical  countries.  It  is 
divided  into  twenty-five  tribes,  many  of  which  differ  so  greatly  from 
each  other  that  they  have  been  regarded  as  orders  by  some  botanists. 

The  most  common  representatives  of  this  order  in  the  United  States 
are  the  species  of  Galium  (Bedstraw  or  Cleavers),  Mitchella  (Partridge 
Berry),  and  Houstonia,  (Bluets). 

Cephalanthm  occidentalis,  the  Button  Bush  of  the  Eastern  United 
States,  is  a  tall  shrub  bearing  glossy  green  leaves  and  spherical  heads 
of  white,  sweet-scented  flowers.  It  deserves  to  be  ranked  among  our 
ornamental  shrubs. 

Pinckneya  pubens,  a  small  tree  of  the  Southeastern  United  States,  is 
known  as  Georgia  Bark,  or  Fever  Tree,  on  account  of  the  medicinal 
qualities  of  its  bark. 

Cinchona,  of  several  species.  This  South  American  genus  contains 
thirty  or  more  species  of  trees  ;  several  of  these,  as  C.  offlcinalis,  C.  cali- 

FIGS.  451-5.— ILLUSTRATIONS  op  COFFEA  ARABIOA.    ALL  MAGNIFIED. 


FIG.  451. 


Fig.  451.— Berry.  Fi^.  452.— Seed  ;  ventral  face. 

Fig.  453.— Seed  ;  dorsal  face.  Fig.  454.— Transverse  section  of  seed. 

Fig.  455. — Dorsal  face  of  seed,  cut  away  to  show  embryo. 


saya,  C.  succirubra,  etc.,  all  natives  of  the  Andean  regions  of  Peru, 
Bolivia,  and  New  Granada,  furnish  the  drug  known  as  Peruvian 
Bark.  This  bark  contains  two  important  alkaloids,  viz.  :  Cinchonia 
(C20  H-H  N2  O),  and  Quinia  (C20  H24  N2  O.,  +  3  Ha  0)  ;  the  latter  as  a 
sulphate  is  the  exceedingly  valuable  medicine,  Quinia  Sulphate,  or 
Quinine.  C.nchona  trees  are  now  cultivated  in  India,  Java,  Mauritius, 
and  Jamaica. 

Cephaelis  Ipecacuanha,  a  pemi-shrubby  plant  of  Brazil,  supplies  from 
its  roots  the  well-known  emetic  Ipecacuanha. 

Coffea  Ardbwa,  the  Coffee  Tree,  a  native  of  Abyssinia,  is  a  small- 
sized  evergreen  tree,  bearing  clusters  of  white  flowers  in  the  axils  of 
the  opposite  glossy  leaves.  The  red  berries  are  about  as  large  as 
cherries,  and  each  contains  two  plano-convex  seeds,  the  coffee  seeds  of 
commerce  (Figs.  451-5).  The  Coffee  tree  was  introduced  into  Arabia 
from  four  to  five  centuries  ago,  and  into  Java,  by  the  Dutch,  about 
two  centuries  ago.  It  has  since  been  taken  to  Brazil  and  other  parts 


518  BOTANY. 

of  South  America,  the  West  Indies,  Ceylon,  India,  and  many  of 
the  Pacific  islands.  Although  originally  from  the  same  species,  the 
Coffee  trees  now  grown  in  different  parts  of  the  world  produce  seeds 
varying  much  in  size,  color,  and  quality  ;  thus  in  "Mocha,"  from 
Arabia  and  Abyssinia,  the  seeds  are  small,  of  a  dark  yellow  color,  and 
when  roasted  produce  an  infusion  of  a  mos-t  delicious  quality  ;  in  "  Java 
coffees  "  the  seeds  are  larger,  of  a  paler  yellow  color,  and  of  scarcely  in- 
ferior quality  to  the  preceding  ;  the  coffees  of  Ceylon,  West  Indies,  and 
Brazil  (the  latter  particularly  known  as  "  Rio ")  have  seeds  of  vary- 
ing sizes,  and  of  a  bluish  or  greenish-gray  color,  and  their  infusions 
are  generally  inferior  to  those  of  the  other  varieties. 

Rubia  tinctoria,  a  perennial  herb,  native  of  the  South  of  Europe  and 
Western  Asia,  is  the  Madder  Plant,  now  grown  in  many  parts  of  the 
world  for  its  roots,  which  yield  the  red  dye  known  as  Madder.  The 
plant  has  whorled  leaves  and  bears  some  resemblance  to  some  species 
of  Galium. 

Among  the  ornamental  plants  of  the  order  are  many  species  of  Gdr- 
denia  from  China  and  Africa,  Ixora,  Partlandia,  Boutardia,  etc. 

Order  Caprifoliacese. — Mostly  woody  plants,  with  generally  zygo- 
morphic  flowers  and  stipulate  leaves.  This  small  family  of  two  hun- 
dred species  is  mostly  confined  to  the  Northern  Hemisphere.  A  dras- 
tic and  purgative  principle  is  common  in  the  plants  of  the  order,  but 
none  of  the  species  are  of  much  importance  in  medicine.  Many  species 
are  ornamental — e.g.,  those  of  Lonicera,  the  Honeysuckles  ;  Symphori- 
carpiis,  the  Snowberries  ;  Diervilla,  the  Bush-Honeysuckles,  one  spe- 
cies from  Japan  called  Weigelia  ;  Viburnum,  the  Snowball,  etc.,  etc. 

Sambucus,  the  Elder,  has  edible  berries,  which  are  much  used  for 
making  into  pies,  preserves,  jellies,  wine,  etc.,  in  many  parts  of  th« 
United  States. 

III.  CHORIPETAL^E  (POLYPETALJS  of  authors).  Plants 
whose  flowers  generally  have  both  calyx  and  corolla,  the  lat- 
ter of  separate  petals. 

590.— Cohort  XXII.  Umbellales. — Flowers  usually  actin- 
omorphic ;  ovary  inferior,  one-  to  many-celled ;  ovules  soli- 
tary, pendulous  ;  seeds  with  endosperm. 

Order  Cornacese. — The  Dogwood  Family.  Shrubs  or  trees,  rarely 
herbs,  with  mostly  opposite  simple  leaves  ;  fruit  a  berry  or  drupe.  A 
small  order  of  about  seventy-five  species,  mostly  of  the  north  temperate 
zone. 

Several  native  and  European  species  of  Cornus  are  cultivated  as  orna 
mental  shrubs. 

Aucuba  Japonica.  from  Japan,  is  a  fine  shrub  of  ihe  flower-gardens. 

The  wood  of  Cornus  floridd ,  the  Flowering  Dogwood  of  the  Eastern 


UMBELLALES. 


619 


Fias.  456-60. — ILLUSTRATIONS  OP  FCENICUI.UM  VULGARE. 
ALL  MAGNIFIED. 


United  States,  is  hard  and  fine-grained,  and  is  sometimes  used  as  a  sub- 
stitute for  Boxwood. 

The  wood  of  Nyssa  multiflora,  the  Sour  Gum,  Tupelo,  or  Peppridge 
tree  of  the  Eastern  United  States,  is  exceedingly  difficult  to  split,  and 
is  much  used  for  making  hubs  for  wagon  wheels. 

Order  Araliaceae. — Shrubs  or  trees,  rarely  herbs,  with  mostly  al- 
ternate compound  leaves  ;  fruit  usually  a  berry  or  drupe.  Species  340, 
mostly  tropical. 

Some  of  the  species  of  A rnlin  are  ornamental — e.g.,  A.  spinosa  and 
A.  raccmosa,  of  the 
Eastern  and  South- 
ern United  States. 

Hedera  Helix,  the 
English  Ivy  of  Eu- 
rope and  Western 
Asia,  is  a  well- 
known  ornamental 
climber. 

Aralia  quinquefo- 
lia,  Ginseng,  is  com- 
mon in  many  parts 
of  the  Eastern 
United  States.  Its 
root  is  officinal. 

Aralia  papyrife- 
ra,  a  small  tree  of 
China,  is  the  source 
of  the  Chinese  Rice 
paper  ;  for  this  pur- 
pose the  pith  is  cut 
into  thin  sheets  and 
then  pressed  flat. 

FIG.  458. 


FIG.  459. 


FIG.  460. 


Fi<?.  456.— Flower. 

Fig.  458.— Flower  diagram. 

Fig.  460.-Section  of  seed. 


Fig.  457.— Section  of  flower. 
Fig.  459.— Ripe  fruit. 


Order  Umbellif- 
erse.— Herbs,  rarely 
shrubs  or  trees,  with 
alternate  and  usual- 
ly much  dissected  leaves ;  fruit  dry  and  indehiscent.  Species  1300, 
found  most  abundantly  in  Northern  Europe  and  Asia,  although  occur- 
ring in  nearly  all  countries.  Many  contain  an  acrid  poisonous  princi- 
ple, and  the  plants  of  the  order  may  usually  be  regarded  with  suspi- 
cion. In  a  general  way  it  may  be  said  that  the  fruits  are  aromatic 
and  innoxious,  and  the  green  parts  acrid  and  poisonous.  (Figs.  456-60.) 

The  Parsnip  (Paiitinaca  satica)  and  the  Carrot  (Daucus  Carotd), 
both  natives  of  Europe,  are  valuable  and  well-known  food  plants. 
In  tlieir  wild  state  they  are  poisonous. 

Apium  graveolens,  Celery,  a  native  of  Europe,  is  deservedly  popular 


520  BOTANY. 

as  a  salad.  The  poisonous  herbage,  when  deprived  of  its  green  color  by 
covering  with  earth,  is  rendered  wholesome. 

Among  the  aromatic  and  medicinal  products  may  be  mentioned  Cara- 
way, Coriander,  Cummin,  Fennel  (Fwniculum  vulgare),  Dill,  Aniseed, 
etc. 

Fei-ula  Asafatida  is  a  tall  growing  plant  of  Thibet  and  the  western 
parts  of  Asia.  The  dried  atid  hardened  milky  juice  of  the  root  is  the 
nauseous  smelling  Gum  Asatetida.  It  is  said  that  the  Persians  hold 
it  in  high  esteem  as  a  condiment.  Gum  Ammoniacum,GumGalbanum, 
Gum  Opopanax,and  some  other  gum  rcsinsare  similar  strong  smelling 
products  of  other  plants  of  the  same  region. 

Conium  maculatum,  Poison  Hemlock,  a  native  of  Europe,  but 
naturalized  in  the  United  States,  is  virulently  poisonous.  It  is  sup- 
posed to  be  the  Hemlock  used  by  the  Greeks  to  poison  their  criminals 
and  other  offenders. 

Cicuta  maculata,  Water  Hemlock,  and  ^Ethtisa  Cynapium,  Fool's 
Parsley,  are  two  common  poisonous  plants,  the  first  a  native  of  the 
Eastern  United  States,  the  second  introduced  from  Europe. 

Monizia  edulis,  of  the  Madeiras,  is  a  low  tree,  and  in  Australia  spe- 
cies of  Xantfiosia,  Traehymene,  Astrotrichia,  etc.,  are  shrubs  or  small 
trees. 

591.— Cohort  XXTEI.  Ficoidales.  Flowers  usually  actin- 
omorphic ;  ovary  mostly  inferior,  one-  to  many-celled ;  pla- 
centae parietal,  basilar  or  axile  ;  seeds  with  or  without  endo- 
sperm. 

Order  Ficoidese.— Mostly  herbs,  often  with  fleshy  leaves.  Specie* 
450,  mostly  tropical,  represented  in  the  United  States  by  the  Carpet- 
weed  (Mottugo  verticillata). 

Mesembryanthemum  crystattinum,  the  Ice  Plant,  is  commonly  culti- 
vated as  a  curiosity. 

Order  Cactaceae.— The  Cactus  Family.  Succulent  herbs,  shrubs, 
or  trees,  often  spiny,  and  generally  leafless.  About  1000  species  are 
enumerated,  all  American  (with  one  or  two  exceptions),  and  mostly 
trojiical.  Several  of  the  species  are  common  in  many  parts  of  the  Old 
World,  having  long  since  escaped  from  cultivation. 

Many  of  the  species  are  grown  in  conservatories  for  their  fine  flow 
ei>,  as  well  as  on  account  of  their  curious  shapes  Cereus  grandi- 
florm,  the  Night  Blooming  Cereus  ;  Opu/itia  mdgaris,  the  common 
Prickly  Pear  ;  0.  coccineUifera,  and  others,  are  common.  The  last- 
named  is  fed  upon  by  the  Cochineal  Insect,  from  which  the  dye  Carmine 
is  derived. 

The  fleshy  fruits  of  some  species  are  edible. 

592.-Cohort  XXIV.  Passiflorales.— Flowers  usually  ac- 
tinomorphic ;  ovary  usually  inferior,  syncarpous,  one-celled, 


PASSIFLORALES. 


521 


with  parietal  placentas  (sometimes  three  or  more  celled  by 
the  produced  placentae). 

Order  Datiscaceae. — A  mrious  order  of  four  species,  one  of  which, 
Datisca  glomerata,  occurs  in  California. 

Order  Begoniaceee. — A  tropical  order  of  350  species  of  herbs,  mostly 
FIGS.  461-5.— ILLUSTRATIONS  OP  CUCUMIS  MBI.O. 


Fig.  461.— Male  flower,  vertical  section. 
Fin.  462.— Female  flower,  vertical  section. 
Fig.  464.— Diagram  of  male  flower. 


FIG.  465. 


Fig.  463. — Andrcecium.    Magnified. 
Fig.  465.— Diagram  of  female  flower. 


American,  represented  in  green-houses  and  conservatories  by  many 
species  of  the  principal  genus  Begonia — e.g.,  B.  Rex,  B.  Evansiana,  B. 
fuchsioides,  etc. 

Order  Cucurbitaceee. — The  Gourd  Family.  Herbs  or  undershrubs 
with  climbing  or  trailing  stems  and  diclinous  flowers ;  placentae  pro. 
duced  to  the  axis  of  the  ovary  and  revolute.  Species  470,  mostly 
tropical.  (Figs.  461-5.) 


522  BOTANY. 

CucurUta  maxima,  the  large  Winter  Squash;  C.  verrucosa,  the  Crook- 
necked  Squash  ;  and  C.  Pepo,  the  Pumpkin,  are  well  known  in  cultiva- 
tion. Their  nativity  is  unknown.  According  to  Dr.  Gray,  the  Pump- 
kin was  "cultivated  as  now  along  with  Indian  Corn  by  the  North 
American  Indians  before  the  coming  of  the  whites." 

Cucumis  Melo,  the  Musk-Melon,  and  C.  sativus,  the  Cucumber,  are 
doubtless  natives  of  India. 

Citrullm  vulgaris,  the  Watermelon,  is  a  native  of  India. 

The  dried  flesh  and  seeds  of  Citrullm  Colocynthis,  of  the  Eastern 
Mediterranean  region,  constitutes  the  poisonous  drug  Colocynth. 

Lagenaria  vulgaris,  the  common  Gourd,  a  native  of  Asia  and  Africa, 
is  cultivated  for  its  fruits,  which  are  made  into  bottles,  drinking  ves- 
sels, etc. 

Luffa  JEgyptica,  the  Towel  Gourd  of  Egypt,  is  now  grown  in  the 
West  Indies  and  the  Southern  United  States.  Its  fruit  is  somewhat 
larger  than  a  Cucumber,  and  is  very  fibrous  internally  ;  its  rind  and 
seeds  are  removed,  and  the  fibrous  portion  used  as  a  bath  sponge. 

Echinocystis  Idbata,  the  Wild  Cucumber  or  Balsam  Apple  of  the 
Eastern  United  States,  is  a  rapidly  growing  climber,  valuable  for  ar- 
bors, screens,  etc. 

Order  Passifloraceae. — The  Passion-Flower  Family.  Trees,  shrubs, 
or  herbs,  mostly  of  the  tropics.  Species  250,  represented  in  the  South- 
ern United  States  by  four  or  five  species  of  Passiflora,  and  in  conserv- 
atories by  magnificent  climbers  of  the  same  genus  from  South  America. 

Carica  papaya,  the  Papaw  of  tropical  America,  is  a  small  tree,  bear- 
ing large  edible  fruits. 

Order  Turneracese. — Tropical  herbs  and  shrubs. 

Order  Loasacese. — Herbs  of  warm  climates,  mostly  American. 

Order  Samydaceee.— Trees  and  shrubs  of  the  tropics. 

593.  Cohort  XXV.— Myrtales.  Flowers  mostly  actino- 
morphic  ;  ovary  usually  inferior,  syncarpous  ;  placentae  in  the 
axis  (or  apical,  rarely  basal) ;  leaves  simple,  and  usually  entire. 

Order  Onagraceee. — Herbs,  shrubs,  and  trees,  about  300  species,  of 
temperate  climates,  represented  in  the  United  States  by  species  of  Epi- 
loliium,  (Enothera,  and  other  genera.  In  conservatories,  many  species 
of  Fuchsia  are  cultivated  for  their  beautiful  flowers.  They  are  natives 
of  Mexico  and  South  America. 

Trapa  natans,  a  curious  aquatic  plant  of  Central  and  Southern 
Europe,  is  called  Water  Chestnut,  and  its  large  nut-like  horned  fruits 
are  nutritious.  T.  bispinosa,  of  Northern  India,  and  T.  bicorni*,  of 
China,  are  extensively  used  for  food  in  their  native  countries. 

Order  Lythraceee.— Herbs,  shrnl-p,  and  trees,  mostly  of  the  tropics. 


MTRTALES.  523 

Species,  250,  represented  in  the  United  States  by  a  few  small  herbs  of 
the  genera  Ly thrum,  Cuphea,  etc. 

Lawsonia  i/iermis,  a  shrub  of  Western  Asia,  has  long  been  in  culti- 
vation in  Egypt  and  the  adjacent  countries.  From  its  leaves  the  cos- 
metic Henna  or  Khenna,  so  much  used  for  coloring  the  hair  and  nails, 
is  made. 

Punica  granatum,  the  Pomegranate  of  India,  is  a  bushy  tree,  six  to 
nine  metres  high  (20-30  feet),  bearing  deciduous  leaves,  and  yellowish 
fruits  about  the  size  of  an  apple.  The  pulpy  interior  of  the  latter  is 
prized  for  making  cooling  drinks ;  from  it  a  wine  is  also  made.  Pome- 
granates have  long  been  grown  in  the  countries  about  the  Mediterranean 
Sea,  and  are  now  cultivated  in  the  warmer  parts  of  America. 

Lagerstrwmia  regince,  the  Jarool  or  Bloodwood  tree  of  India,  is  highly 
valued  for  its  blood-red  wood,  which,  being  exceedingly  durable  in 
water,  is  much  used  in  shipbuilding. 

L.  Indica,  a  common  green-house  shrub  from  India,is  cultivated  under 
the  name  of  Crape  Myrtle. 

Sonneratia  acida,  an  Indian  tree,  yields  a  most  valuable  fuel. 

Physocalymma  floribunda,  the  Tulip  tree  of  Brazil,  yields  a  fine 
wood  much  used  for  inlaying. 

Order  Melastomaceae. — Trees,  shrubs,  and  a  few  herbs,  of  the 
tropics.  Species,  1800.  We  have  in  the  United  States  but  one  genus, 
Rliexia,  represented  by  half  a  dozen  species.  A  few  are  cultivated  in 
green-houses. 

Order  Myrtaceee.— The  Myrtle  Family.  Trees  and  shrubs  (rarely 
herbs),  with  mostly  opposite  glandular-dotted  leaves ;  stamens,  many. 
A  large  and  very  difficult  order  of  1800  or  more  species,  which  are  dis- 
tributed throughout  the  tropics  and  the  Southern  Hemisphere. 

Many  of  the  species  yield  excellent  fruits. 

Psidium  pomiferum  and  P.  pyriferum,  of  the  West  Indies,  and  P. 
Cattleyaiium,  of  Brazil,  bear  apple-  or  pear-shaped  fruits  called  Guavas, 
highly  esteemed  for  dessert,  and  for  preserving.  All  are  now  exten- 
sively grown  in  tropical  climates. 

Eugenia  ma7accensis,  the  Malay  Apple,  and  E.  Jambos,  the  Rose 
Apple,  both  of  the  East  Indies,  furnish  important  fruits  to  the  people 
of  the  far  East. 

E.  pimenta,  a  West  Indian  tree,  is  there  cultivated  for  its  berries, 
which  are  gathered  and  dried  before  ripening,  constituting  the  Pimento 
or  Allspice  of  commerce. 

E.  aromatiea,  the  Clove  Tree  of  the  Moluccas,  now  extensively  cul- 
tivated in  the  East  and  West  Indies,  is  prized  for  its  spicy  flower-buds, 
which  are  gathered  before  opening  and  then  dried,  in  which  state  they 
are  known  as  Cloves. 

Bertkolletia  excelsa,  of  tropical  America,  is  a  tree  thirty  to  forty-five 
metres  high  (100-150  feet),  bearing  woody-shelled  fruits,  ten  to  fifteen 


524 


BOTANY. 


cm.  (4-6  inches)  in  diameter,  inside  of  which  are  a  number  of  rough 
oily  seeds,  the  Brazil  Nuts  of  commerce.  Closely  related  to  this  is  the 
Monkey  Pot,  whose  woody-shelled  liuit  is  dehiscent  by  a  circular  lid. 

Many  of  the  trees  of  this  order  furnish  valuable  timber. 

Myitus  communis,  the  Myrtle  Tree  of  Western  Asia,  yields  a  hard 
mottled  wood  much  esteemed  in  turnery.  (Fig.  466.) 

Eucalyptus,  sp.,  the  Gum  Trees  of  Australia  and  Tasmania.  These 
are  large  stately  trees,  often  rising  to  the  height  of  fifty  to  one  hun- 
dred metres  (150-300  feet),  and  occasionally  even  exceeding  this.  The 
timber  furnished  by  them  is  in  some  cases  of  great  value,  being  tough 
and  durable.  (Figs.  467-8.) 

E.  globulux,  the  Blue  Gum,  is  now  much  planted  in  California.  Its 
timber  is  valuable,  but  shrinks  greatly  in  drying.  E.  inarginatn.  "  the 
Jarrah  or  Mahogany  tree  of  Southwestern  Australia  is  famed  for  its  in- 
destructible wood,  which  is  attacked  neither  by  Chelura,  Teredo,  nor 


Fig.  466.— Vertical  section  of  the  flower  of  Myrlua  communis.    Magnified. 
Fig.  467.— Vertical  section  of  the  flower  bud  of  Euealyptus  globulu».    Nat.  size. 
Fig.  468.— Transverse  section  of  the  ovary  of  Eucalyptus  globulus.    Magnified. 

Termes,  and  therefore  much  sought  for  jetties  and  other  structures  ex- 
posed to  sea  water,  also  for  underground  work,  and  largely  exported 
for  railway  sleepers.  Vessels  built  of  this  timber  have  been  enabled 
to  do  away  with  copper-plating."  (Mueller).  E.  resinifem,  the  Iron 
Bark  tree  supplies  a  very  heavy  and  exceedingly  strong  timber. 
Species  of  Eugenia,  Myrtus,  etc.,  are  grown  in  conservatories. 

Order  Combretaceee. — Tropical  trees  and  shrubs,  about  240  species. 
A  few  species  occur  in  South  Florida. 

Order  Rhizophoraceae. — Tropical  trees  and  shrubs,  about  50  spe- 
cies, the  most  important  of  which  is  the  Mangrove  Tree  of  tropical 
America  (Rhizophora  Mangle) ;  it  also  occurs  from  Florida  to  Texas. 

594.  Cohort  XXVI.— Resales.  Flowers  mostly  actino- 
morphic ;  carpels  one  or  more,  usually  quite  free  in  bud, 


ROSALES.  525 

sometimes  variously  united  afterwards  with  the  calyx-tube, 


Fig.  469.— IHoncea  miitclpula.    Plant  with  flower-stalk.    Natural  size. 
Fip  470 —Flower-cluster.     Natural  size. 
Fig.  4Tl.-Pi8til  cut  vertically.    Magnified. 

or  enclosed  in  the  swollen  top  of  the  peduncle  ;  styles  usu- 
ally distinct. 
Order  Haloragew,— Mostly  aquatic  herbs,  about  eighty  species, 


526  BOTANY. 

Order  Bruniaceee.— A  few  heath-like  woody  plants  of  South  Africa. 

Order  Hamamelaceee.— A  small  order  of  trees  and  shrubs,  repre- 
sented in  the  United  States  principally  by  the  Witch  Hazel  (Hania- 
melisVirginicu),  and  the  Sweet  Gum  Tree  (Liquidamber  Styraciflua). 

Order  Droseracese.— The  Sundew  Family.  Mostly  bog-herbs  with 
radical  gland-bearing  leaves.  About  110  species  are  known,  distributed 
throughout  the  world.  This  interesting  little  family  has  attracted 
great  attention  on  account  of  the  insect-catching  habits  of  its  species. 

The  most  remarkable  plant  of  the  order  is  the  Venus'  Fly-Trap  (Dioiicea 
muscipula)  of  North  Carolina.  Each  leaf  has  a  rounded  blade  which 
is  fringed  with  stiff  bristles  (Fig.  469),  and  upon  the  surface  of  each  half 
are  three  sensitive  hairs  which,  when  touched,  cause  the  tissues  of  the 
upper  surface  of  the  midrib  to  contract  suddenly,  and  thus  to  quickly 
close  the  leaf  as  a  book  or  rat-trap  is  closed.  An  insect  alighting  upon 
one  of  these  leaves  is  caughtby  the  quickly-closing  sides,  and  is  within 
a  few  days  dissolved  (digested)  by  an  acidulous  fluid  exuded  by  the 
glands  of  the  leaf ;  it  is  then  absorbed  by  the  leaf,  and  when  this  is  ac- 
complished the  latter  again  opens.  This  plant  is  thus  a  partial  sapro- 
phyte ! 

In  the  Sundews  (species  of  Drosera),  the  leaves  have  stalked 
glands  which  are  sensitive,  and  when  these  come  in  contact  with  an 
insect  they  cause  the  blade  to  slowly  bend  around  it,  finally  enclosing 
it.  Digestion  and  absorption  then  take  place  as  in  the  previous  case. 

Mr.  Darwin  has  shown  that  the  other  genera  of  the  order  are  also  in- 
sectivorous. (See  his  book,  "Insectivorous  Plants,"  London  and  New 
York,  1875,  in  which  367  pages  are  devoted  to  the  plants  of  this  order). 

Order  Crassulacese.— Herbs  or  undershrubs,  usually  with  thick 
fleshy  leaves.  Species  400,  found  mostly  in  temperate  climates.  Many 
are  in  common  cultivation — e.g.,  Bryophyllum,  the  Live-leaf  from 
tropical  Africa  ;  Crassula,  of  many  species,  from  the  Cape  of  Good 
Hope  ;  Cotyledon,  of  many  species,  from  Mexico  and  Africa  ;  Sedum, 
Live-forever  ;  Sempervivum,  the  Houseleek,  etc. 

Order  Saxifragacese.— The  Saxifrage  Family.  Trees,  shrubs,  and 
herbs  with  actinomorphic  flowers,  generally  definite  stamens,  and 
seeds  rich  in  endosperm.  Species  540,  mostly  natives  of  temperate  and 
cold  climates. 

Ribcs  grossularia,  the  Gooseberry,  and  R.  rubrum,  the  Red  Currant, 
both  of  Europe,  are  in  common  cultivation  for  their  edible  berries. 
The  last  named  is  also  indigenous  northward  in  this  country. 

Among  ornamental  plants  are  Philadelphus,  the  Mock  Orange,  from 
the  Old  World  ;  Ribes,  Flowering  Currants,  of  the  Western  United 
States  ;  Deutzia,  from  China  and  Japan  ;  Hydrangea,  Japanese  and 
native;  Astllbe,  from  Japan  ;  Saxifraga  sarmentosa,  the  so-called  Straw- 
berry Geranium,  a  fine  basket  plant  from  China. 

Cephalotus  fotticularis,  the  Australian  Pitcher  Plant,  is  now  regarded 


BOS  ALES. 


as  a  member  of  this  order.  It  is  a  low  plant  with  a  rosette  of  radical 
leaves,  some  of  which  resemble  the  covered  pipes  used  by  many 
Frenchmen  (Fig.  472).  The  border  of  the  ascidium  (pitcher)  in  the  lat- 
ter is  incurved  and  presents  an  obstacle  to  tlie  egress  of  insects,  which 
are  no  doubt  thus  captured. 

Order  Rosaceas. — The  Rose  family.  Herbs,  shrubs,  and  trees, 
usually  with  actinomorphic  flowers,  generally  indefinite  (many) 
stamens,  and  seeds  destitute  of  endosperm.  Species,  1000,  distributed 
throughout  the  world.  The  plants  here  under  consideration  have  been 
arranged  under  several  orders  by  some  authors,  on  account  of  a  part 
having  an  apparently  inferior  5-celled  ovary,  others  many  superior 
ovaries,  and  still  others 
but  one  superior  ovary. 
Bentham  and  Hooker 
have  arranged  the  sev- 
enty-one genera  under 
ten  tribes,  eight  of 
which  only  will  be  no- 
ticed here. 

Tribe  Fomece.— 

Shrubs  and  trees  with, 
simple  leaves,  ovaries 
5-  (rarely  less),  adnate 
to  and  frequently  cov- 
ered by  the  fleshy  re- 
ceptacle (and  calyx  ?). 

Pirus    Mains,     the 
Apple,  and  P.  commu- 
nis,   the    Pear,    grow 
wild  in  many  parts  of  Europe.     They  have  been  cultivated  for  ages  in 
other  portions  of  the  world.     (Fig.  473.) 

P.  prunifolia  and  P.  baccata,  Siberian  Crab-Apples,  of  the  North  of 
Asia,  are  in  common  cultivation. 

P.  coronaria,  the  American  Crab-Apple, of  the  Eastern  United  States, 
might  be  made  a  valuable  apple  by  cultivation. 

P.  Cydonia  (or  Cydonia  vulgaris),  the  Quince,  is  a  native  of  the 
Levant.  (Figs.  474-5.) 

The  Hawthorns  (Cratcegus,  sp.)  are  of  some  value  for  their  fruits, 
and  have  long  been  favorites  for  hedges  and  ornamental  purposes, 
Service-berries  (Amelanchier,  sp.)  furnish  valuable  fruits,  and  are 
ornamental. 

Tribe  Rosece. — Shrubs,  with  pinnately  compound  leaves  ;  ovaries 
many,  free,  but  surrounded  by  the  fleshy  receptacle  (and  calyx?). 

Rosa — of  many  species — the  Roses.  Not  only  are  our  native  species 
(of  which  we  have  about  a  dozen)  more  or  less  cultivated  for  their  beau- 


Fig.  472.— Leaves  of  Cephalotusfollicularis.  f,  normal 
foliage  leaf  ;  f",  ascidium  ;  6,  its  incurved  border ;  f. 
its  lid.  Natural  s  ze. 


BOTANY. 


tiful  flowers,  but  from  eighteen  to  twenty  or  more  species  from 
Europe  and  Asia  are  commonly  to  be  found  in  gardens  and  conser- 
vatories. (Fig.  476.) 

Tribe    Potentillece. — Mostly    herbs,    with    usually    compound 

FIGS.  473-5.— ILLUSTRATIONS  OP  TRIBE  POMB^E. 


FIG.  473. 


PIG.  474.  Fie.  476. 

Fig.  473. — Flower  cluster  of  ni"u»  communis. 

Fig.  474.— Section  of  Quince  flower  (Firm  Cydonia). 

Fig.  475.-Section  of  Quince  fruit. 

leaves  ;  carpels  free,  one  to  many,  mostly  on  a  convex  fleshy  receptacle  ; 
fruits  dry  (achenia). 

Frngnria  eltttior,  of  Europe,  F.  rewa,  of  Europe  and  Eastern  United 


ROSALE8.  539 

States,  and  F.  Virginiana  of  the  Eastern  United  States,  are  the  specie* 
from  which  the  cultivated  Strawberries  have  been  derived,  by  higli 
culture  and  crossing.  (Fig.  477.) 

Chamaibittia  foliosa  of  the  western  slope  of  the  Sierra  Nevada  Moun- 
tains in  California,  is  a  small  fragrant  shrub  with  thrice  pinnate  leaves, 
much  gathered  by  tourists,  and  deserving  a  place  in  gardens. 

Cercocarpus  ledifoliu,*,  the 
Mountain  Mahogany,  of  Califor- 
nia, is  a  shrub  or  tree,  ranging 
from  two  to  fifteen  metres  in 
height  (6  to  50  feet).  Its  heavy 
dark  colored  wood  is  valuable. 


Tribe  Rubece.  —  M  o  s  1 1  y 
shrubs,  differing  from  the  pre- 
ceding in  having  fleshy  fruits 
(drupes). 

Rubus  Idceus,  the  Garden  Rasp- 
berry, of  Europe,  is  also  cultivat- 
ed to  some  extent  in  this  country.  Fig.  476.— Section  of  the  flower  of  Rom 

R.      OCddentalis,     the     Black    ruMginosa.    Natural  rise. 
Raspberry,  and   R.  strigosus,  the  Red  Raspberry,  both  natives  of  the 
Eastern  United  States,  have  given  rise  to  the  Common  Raspberries  of 
our  gardens. 

R.  fruticosus,  the  Blackberry,  of  Europe,  is  scarcely,  if  at  all  culti- 
vated in  this  country.  R.  villosus,  the  Wild  Blackberry,  of  the  Eastern 

United  States,  is  exten- 
sively cultivated. 

Tribe  Quillajece. 
— Trees  and  shrubs, 
with  mostly  simple 
leaves,  dry  fruits  and 
winged  seeds.  Nearly 
all  are  natives  of  Mexico 
or  South  America. 

Quillaja  saponaria,  of 
Chili,  is  an  evergreen 

°f  th<S  fl°Wer  °f  Fragaria  vesca-  tree,  fifteen  to  eighteen 
metres  (50  to  60  feet) 
high,  whose  bark  contains  Saponin  (C3a  H64  018),  and  is  used  instead 
of  soap  for  washing.  Under  the  name  of  Soap-bark  or  Quillaja-bark 
it  is  imported  into  this  country. 

Tribe  Spirceece.— Mostly  woody  plants,  of  the  Northern  Hemi- 
sphere, with  dry  fruits.  The  principal  genus  Spiraea,  contains  many 
species,  which,  being  highly  ornamental,  are  commonly  planted  in 
flower-gardens. 


530  BOTANY. 

Tribe  Prunece. — Trees  and  shrubs,  with  stems  yielding  gum, 
simple,  mostly  serrate  leaves,  and  solitary  carpel  ripening  into  a 
drupe.  (Figs.  478-9.) 

Prunus  communia,  the  Almond,  is  a  native  of  Western  Asia,  and 
now  grown  in  many  warm-temperate  countries  for  its  fruits.  Two 
principal  varieties  are  grown,  viz..  Sweet  and  Bitter  ;  in  the  former  the 
kernel  is  ediblo,  whereas,  in  the  latter,  it  is  bitter  and  poisonous.  An 
oil  is  expressed  from  both  kinds. 

The  Peach  has  been  until  recently  regarded  as  a  distinct  species 
(P.  Persico),  but  it  is  now  supposed  to  have  been  derived  from  the 
Almond,  by  long  culture  and  selection. 

P.  Armeniaca,  the  Apricot,  originally  from  Armenia,  is  now  exten- 
sively grown  in  many  countries. 

P.  domestica,  the  Plum  of  Europe,  P.  Americana,  the  Common  Wild 


Fie.  478.  FIG.  479. 

Fig.  478. — Flower  cluster  of  Prunus  Cerasut. 

Fig.  479.— Section  of  flower  of  the  Peach.    Magnified. 

Plum,  of  the  Eastern  United  States,  and  P.  Chicasa,  of  the  Southern 
States,  are  cultivated  for  their  excellent  fruits.  The  second  named  is 
the  original  form  of  most  of  the  varieties  grown  in  the  central  part  of 
the  United  States. 

The  Cherry,  commonly  referred  to  P.  Cerasus,  is  probably  derived 
from  P.  aviiim,  the.  Bird  Cherry,  of  Europe.  The  wood  of  the  Bird 
Cherry  is  used  in  Europe  for  making  furniture,  as  is  also  that  of  our 
Wild  Black  Cherry  (P.  serotina),  of  the  Eastern  United  States. 

Many  of  the  foregoing  have,  by  long  and  careful  culture,  developed 
double-flowered  varieties,  which  are  sometimes  to  be  found  in  gardens. 

Prunus  nana,  the  Dwarf  Almond,  is  well  known  in  the  double- 
flowered  state. 

Tribe  Chrysobalanece.— Trees  and  shrubs,  with  simple,  entire 
leaves.  Mostly  natives  of  tropical  America,  a  few  of  tropical  Asia  and 


ROSALES. 


531 


Africa.  Some  of  the  latter  bear  edible  fruits.  The  bark  of  Brazilian 
trees  of  the  genera  Licania  and  Coutpia  is  paid  to  contain  such  consid- 
erable quantities  of  silica,  that  it  is  burnt  by  the  natives  and  used  in 
the  manufacture  of  pottery. 

Order  Leguminosse.— The  Pulse  Family.  Herbs,  shrubs,  and 
trees,  with  alternate  and  usually  compound  leaves  ;  flowers  for  the  most 
part  zygomorphic  ;  stamens  usually  twice  as  many  as  the  petals  ;  pistil 

FIGS.  480-6.— ILLUSTRATIONS  OF  PAPILIONACE.*:. 
(480-5,  Lathyrua  odoratus.) 


FIG.  484 


480. 


Fig.  480.— Section  of  flower.    Magnified.        Fig.  -J81. -Diagram  of  flower. 
Fi.'.  482.— Calyx.    Magnified.  Fig.  483.—  Stamens  and  pistil.  Mag. 

Fig.  484.— Ripe  fruit.  Fig.  485.— Part  ol  fruit,  with  a  seed. 

Fig.  486.-Section  of  seed  of  Tetragonolobus.    Magnified. 

monocarpellary  and  free  ;  seeds  generally  wanting  an  endosperm.     A 
vast  order  of  6500  species,  distributed  throughout  the  world. 

The  species  are  usually  disposed  in  three  sub-orders,  each  containing 
many  tribes. 

Sub-Order  I.  Papilionacece,  with  zygomorphic  flowers  ;  sta- 
mens generally  ten,  monadelplious  or  diadelphous.  This  sub-order 
contains  a  large  number  of  plants  of  great  economic  importance. 

The  food  plants  include  the  Pea  (Pisum  sativum),  the  so-called  English 
Bean  (Vicia  fdba),  the  Pole  Bean  (Phnseolw  vu'garia),  the  Field  Bean 


532  BOTANY. 

(P.  nana),  the  Lima  Bean  (P.  lunatus),  probably  all  from  India  and 
Western  Asia. 

Many  more  species  are  now  cultivated  in  India,  such  as  Chowlee, 
Black  Grain,  Soy,  Pigeon  Pea,  Lentils,  etc. 

The  Peanut  (Arachin  hypog&a),  a  native  of  South  America,  is  now  an 
important  food  plant  in  the  West  Indies  and  Africa.  After  the  fertili- 
zation of  the  erect  yellow  flowers,  the  peduncles  bend  down  and  the 
young  pods  are  thrust  into  the  ground,  where  they  ripen.  This  curi- 
ous habit,  which  must  have  been  at  first  a  protective  one,  is  perpetu- 
ated in  cultivation,  although  the  need  of  it  apparently  no  longer  exists. 

The  forage  plants  include  the  Red  Clover  (Trifolium  pratense),  the 
White  Clover  (T.  repens),  Lupine  (Lupinus  attms),  Lucerne  (Medicayo 
xiitiva),  Sanfoin  (Onobrychus  sativa),  Tares  or  Vetches  ( Vicia  saliva), 
all  from  Europe  and  the  countries  adjacent  to  the  Mediterranean  Sea. 
Many  others  are  grown  less  extensively. 

Of  the  timber  trees,  the  following  are  the  most  important  : 

Robinia  Pseud-Acacia,  the  Locust  Tree  of  the  Eastern  United  States, 
yields  a  very  strong  and  durable  timber. 

Dalbergia  tiigra,  a  large  tree  of  6ra7.il,  produces  the  finest  Rose- 
wood. 

D.  latifolia,  of  India,  produces  the  Indian  Rosewood. 

The  valuable  dye  Indigo  is  obtained  from  Indigoftra  tinctoria,  a 
native  of  India.  The  flowering  plants  are  cut  and  placed  in  vats  of 
water  ;  after  remaining  for  a  time,  the  water,  now  colored,  is  drawn  off, 
and  after  several  intervening  processes,  the  coloring  matter  is  allowed 
to  settle  to  the  bottom  ;  this  when  dried  is  crude  indigo. 

The  wood  of  Ptero  arpus  tantalinu*,  a  tree  of  India,  when  reduced 
to  chips,  is  the  red  dye  known  as  Red  Sandal-wood,  or  Saunders. 

Camwood,  another  red  dye,  is  obtained  in  a  similar  manner  from 
Baphia  nitida,  a  West  African  tree. 

Some  species  furnish  gums  and  balsams,  which  are  of  use  in  the  arts. 

Gum  Tragacanth  is  derived  from  a  low  shrubby  plant,  Astragalut 
tragacantha,  growing  in  Western  Asia. 

Gum  Kino  is  produced  by  large  trees  of  India  and  Africa  belonging 
to  the  genus  Pterocarpus. 

6alsam  of  Peru  and  Balsam  of  Tolu  are  the  products  of  species  of 
Myroxylon,  in  Central  and  South  America. 

But  one  important  medicinal  product  is  furnished  by  this  sub-order, 
viz.,  Liquorice,  the  dried  roots  of  Glycyrrhiza  glabra,  a  native  herb  of 
the  South  of  Europe. 

In  India  species  of  Crotalaria  and  Sesbania  are  extensively  cultivated 
for  their  strong  and  durable  fibre,  much  used  for  making  cordage  and 
coarse  cloth. 

Of  the  muay  ornamental  plants,  the  following  only  can  be  mentioned, 
viz.,  species  of  Lupinus,  Cyiisus,  Laburnum,  Petalostemon,  Caragana. 
Itofiinia,  Wistaria,  PAaseolus,  Lathyrus,  Sophora,  etc.,  etc. 


R08ALE8.  533 

Desmodium  gyrans,  rn  Eas*  Indian  plant,  is  remarkable  for  the 
spontaneous  movements  of  its  leaves.  The  leaves  are  compound,  the 
terminal  leaflet  being  large,  while  the  lateral  ones  are  small  ;  under 
proper  conditions  the  lateral  leaflets  alternately  rise  and  fall  by  quick 
jerks,  continuing  this  for  hours  without  any  apparent  external  cause. 

Sub-Order  II.  Cce.ttitpiniece,  with  flowers  zygomorphic  or  ac- 
tinomorphic ;  stamens  generally  ten,  usually  distinct. 

The  Tamarind  is  the  fruit  of  a  North  African  and  East  Indian  tree  of 
this  sub-order,  Tamarindus  Indica. 

Senna,  a  medicinal  drug,  is  the  dried  foliage  of  African  and  East 
Indian  species  of  Cassia. 

Gum  Copal,  much  used  in  making  varnishes,  is  derived,  at  least  in 
part,  from  East  Africa  and  Madagascar  trees  belonging  to  the  genera 
TracJiylobium  and  Hymencea. 

Copaiva  Balsam  is  obtained  from  Brazilian  trees  (Copaifera,  pp.)  by 
making  deep  incisions  into  the  trunks. 

The  pulverized  wood  of  Casalpina  echinata,  a  Brazilian  tree,  yields 
the   red  dye  Brazil-wood  ;   that   from   Hcematoxylon 
Campeachianum,  a  small  tree  of  Central  America,  is 
the  well-known  and  valuable  dark-red  dye  Logwood. 

Many  timber  trees  are  of  great  value — e.g.,  the 
Mora  Tree  of  Guiana  (Dimwphandra  Mora},  whose 
heavy  durable  timber  is  in  great  repute  in  the  British 
navy  yards  ;  the  West  India  Locust  (Rymencea  Cour-  p. 
baril),  used  in  ship-building ;  the  Honey  Locust  of  the  section  of  the  peed 
Eastern  United  States  (Gledittcliia  triacantlios),  which  ^owinflhe  abuu' 
furnishes  a  valuable  timber  used  by  wheelwrights  dant  endosperm.— 
for  making  hubs ;  the  Kentucky  Coffee  Tree  of  the  Ma£nlfled- 
Eastern  United  States  (Gymnodadus  Canadensis),  whose  red  wood 
somewhat  resembles  Mahogany  ;  the  Judas  Trees  (Cercis,  sp.),  whose 
wood  is  prized  in  Europe  for  cabinet-making. 

Sub-Order  III.  Mimosece. — Flowers  actinomorphic,  small, 
and  generally  collected  into  close  heads  or  spikes  ;  stamens  distinct, 
two  to  many  times  the  number  of  petals. 

One  of  the  most  important  of  the  vegetable  gums — Gum  Arabic  or 
Gum  Acacia — is  furnished  by  trees  of  this  sub-order  belonging  to  the 
genus  Acacia.  The  greatest  supply  is  obtained  from  A.  vera  and  A. 
Arabica,  natives  of  Northern  Africa,  Arabia,  and  the  East  Indies. 

The  genus  Acacia  is  abundantly  represented  in  Australia,  where 
many  of  its  species,  called  Wattles,  yield  most  excellent  timber.  That 
of  A.  melanoxylon  "is  most  valuable  for  furniture,  railway  carriages, 
boat-building,  casks,  billiard-tables,  piano-fortes  (for  pounding-boards 
and  actions),  and  numerous  other  purposes.  The  fine-grained  wood  is 
cut  into  veneers.  It  takes  a  fine  polish,  and  is  considered  equal  to  the 
best  walnut."  (Mueller.) 


534  SOT  ANT. 

Lysiloma  SdMcu,  a  large  Cuban  tree,  yields  a  bard  and  very  durable 
timber,  highly  valued  for  ship-building  and  for  other  purposes. 

Many  species  of  Acacia  and  Mimosa  are  in  cultivation  in  gardens  and 
conservatories. 

Mimosa  pudica,  from  South  America,  is  interesting  on  account  of  its 
extreme  sensitiveness  to  a  touch  or  jar.  On  this  account  it  is  commonly 
known  as  the  Sensitive  Plant.  Its  leaves  expand  in  the  light  and  con- 
tract in  darkness,  and  in  the  proper  temperature  close  at  once  upon 


Pie.  488.  FIG.  489. 

Fig.  488. — Expanded  compound  leaf  of  Mimosa  pudica. 
Fig  489.— Closed  leaf  of  the  game. 

being  touched  or  jarred,   opening  again,  however,  in  a  few  minutes 
(Figs.  488-9). 

Order  Connaraceee.— Trees  and  shrubs  of  the  tropics,  one  of  which, 
Connarns  Lambertii  of  Guiana,  furnishes  the  beautiful  Zebra-wood. 

595.— Cohort  XXVII.  Sapindales.  Shrubs  and  trees, 
with  usually  compound  leaves.  Flowers  often  zygomorphic 
and  diclinous  ;  ovary  superior  ;  seeds  usually  without  endo- 
sperm. 

Order  Moringeee. — Contains  three  Old  World  trees,  of  doubtful 
affinity. 

Order  Coriarieae.— Shrubs  of  one  genus  and  three  to  five  species, 
found  in  the  Mediterranean  region,  the  Himalayas,  Japan,  New  Zea- 
land, and  South  America.  Their  affinities  are  very  obscure. 

Order  Anacardiacese.— The  Cashew  Family.  Trees  and  shrubs, 
with  gummy  or  milky-resinous  juice,  oft*-n  poisonous  ;  fruit  usually  a 
drupe.  Species  about  450,  chiefly  found  in  the  tropics.  The  common 


SAPINDALES.  535 

representatives  of  this  order  in  this  country  are  species  of  Rhus,  of 
which  R.  typhina  and  R.  glabra,  Sumach,  are  highly  ornamental,  as 
well  as  useful,  their  young  shoots  and  leaves  containing  much  tannin 
and  being  much  used  in  tanning. 

Rhus  Toxicodendron,  the  Poison  Ivy,  and  R.  venenata,  the  Poison 
Sumach,  Ijoth  of  the  Eastern  United  States,  and  R.  diversiloba,  the 
"Poison  Oak"  of  California,  are  very  poisonous,  causing  in  many  per- 
sons a  severe  cutaneous  eruption. 

Mangifera  Indica,  of  India,  hut  now  grown  in  most  warm  climates, 
produces  the  excellent  fruit  known  as  the  Mango. 

The  Cashew  Nut  is  the  product  of  a  large  West  Indian  tree,  Anacar- 
(Jium  occidentale,  and  the  Pistachia  Nut  of  a  tree  of  Western  Asia, 
Pistacia  vera. 

Mastic,  a  resinous  material  used  in  fine  varnishes,  is  obtained  by 
making  incisions  into  the  stem  of  Pistacia  Lentiscus,  a  small  tree  of 
the  Mediterranean  region.  Japan  Lacquer,  so  much  used  by  the 
Japanese  in  the  manufacture  of  many  wares,  is  obtained  in  a  similar 
way,  from  Rhus  vernicifera,  and  probably  other  species.  Japanese 
Wax  is  derived  from  the  waxy-coated  seeds  of  R.  succedaneum,  a  tree 
of  China  and  Japan. 

Schinus  motte,  a  Peruvian  shrub,  is  much  grown  for  ornament  in  the 
gardens  of  California  and  Italy,  f^,  *P\J/.LSir  /vVt) 

Order  Sabiaceee. — Trees  and  shrubs,  mostly  of  the  tropics. 

Order  Sapindaceae. — Trees  and  shrubs  (rarely  herbs),  mostly  with 
compound  or  lobed  leaves.  Species  from  600 to  700,  widely  distributed. 
This  order  includes  five  well-marked  sub-orders,  as  follows: 

Sub-Order  I.  Staphylece,  with  actinomorphic  flowers,  and 
seeds  with  endosperm.  Represented  in  the  Eastern  United  States  by 
the  native  ornamental  shrub,  the  Bladder  Nut  (Staphylea  trifolia). 

Sub-Order  II.  Melianthece,  with  zygomorphic  flowers,  and 
seeds  with  endosperm.  Old  World  trees  and  shrubs. 

Sub-Order  III.  Dodoncece,  with  actinomorphic  flowers,  and 
seeds  without  endosperm  ;  leaves  alternate. 

Ptceroxylon  utile,  the  Sneezewood  Tree  of  the  Cape  of  Good  Hope, 
furnishes  a  hard  and  durable  timber,  as  also  a  New  Zealand  tree, 
Alecti-yon  excelsum. 

Sub-Order  IV.  Acerlnece,  with  actinomorphic  flowers,  and 
seeds  without  endosperm  ;  leaves  opposite.  (Figs.  490-2.) 

The  genus  Acer,  the  Maples,  contains  nearly  all  the  species. 

A.  campestre,  the  Common  Maple  of  Europe,  A.  Pseudo  Platanus, 
the  Sycamore  Maple  of  Europe  and  Western  Asia,  and  A.  platan&ides, 
the  Norway  Maple  of  Europe,  are  valuable  timber  trees,  occasionally 
planted  here  as  ornaments. 

A,  taccharinum,  the  Sugar  Maple,  A.  nibrum,  the  Bed  Maple,  and 


636 


BOTANY. 


A.  daaycai'pum,  the  Silver  Maple,  nil  of  the  Eastern  United  States, 
furnish  timber  much  used  in  the  uianulacture  of  furniture. 

From  the  sweet  sap  of  the  first  much  sugar  is  made  in  the  Northern 
United  States.  Its  wood  also  is  harder,  and  is  known  as  Hard  Maple, 
to  distinguish  it  from  Soft  Maple,  derived  from  the  other  species. 

A.  macrophyllum,  the  Large  Leaved  Maple,  and  A.  circinatum,  the 


Pias  490-3.— ILLUSTRATIONS  OF  AOBB  PSEUDO-PLATANUS. 


FIG.  4<«. 


Fig.  490.— Section  of  flower.    Magnified. 
Fig.  492. -Ripe  fruit. 


Pig.  491. -Flower  diagram. 


Vine  Maple,  both  of  California  and  Oregon,  yield  a  hard  and  close- 
grained  timber. 

Negundo  aceroides,  the  Box  Elder  of  the  Eastern  United  States,  is  a 
fine  ornamental  tree.  N.  Californicum,  of  the  Pacific  Coast,  is  much 
like  the  preceding. 

Sub-Order  V.  Sapindecp. — Flowers  actinomorphic  or  zygomor- 
phic ;  seeds  without  endosperm  ;  leaves  mostly  alternate.  (Fig  493.) 


(J EL  AST  RALES. 


53? 


glabra,  the  Ohio  Buckeye,  and   several  other  species,  are 
native  ornamental  trees  of  the  sub-order. 

JE.  Hippocastanum,  the  Horse-Chestnut  of  the  Old  World,  is  com- 
monly planted. 

Kcelreuteria  paniculata,  a  Chinese  tree,  and  Cardioapermum  Halica- 
cabum,  the  Balloon  Vine  of  the  Southern  United  States,  are  cultivated 
as  ornaments. 

Nephelium  LilcJd,  a  small  Chinese  tree,  produces  the  pulpy  edible 
fruits  imported  under  the  name  of  Litchi.  N.  Longan  produces  the 
similar  fruit  called  Longan. 

Melicocca  bijuga,  &  tree  of  Guiana,  yields  a  hard  and  heavy  timber, 
and  from  Cupania  pendula,  of  Australia,  is  obtained  Tulip  Wood, 
which,  in  some  respects,  resembles  Mahogany. 

The  stem  of  the  climbing  plant,  Pauttinm  curassavica,  of  Venezuela, 
is  made  into  the  walking-sticks  called  "  Supple  • 

Jacks." 

596.  —  Cohort  XXVHI.  Celastrales. 
Flowers  actinomorphic  and  monoclinous; 
ovary  superior  entire  ;  seeds  usually  with 
endosperm. 

Order  Ampelideee.  —  Mostly  climbing 
shrubs,  with  nodose  sterns,  bearing  petioled  al- 
ternate leaves  ;  tendrils  and  flower  clusters  op- 

posite  to  the   leaves.      About  250  species  are    the  normal  circle  of  stt- 
known;  they  abound  in   the   tropics  and  are 
much  rarer  in  temperate  climates. 

Vitis  is  the  principal  genus  ;  it  contains  all 
the  true  Vines  (grape  producing),  and  many 
others  whose  fruits  are  inedible.  (Figs.  494-501.) 

Vitis  mnifera,  the  Vine  of  the  Old  World,  has  been  under  cultiva- 
tion from  time  immemorial.  It  is  indigenous  to  Southern  Asia,  from 
whence  it  has  been  carried  to  nearly  all  parts  of  the  world.  Its  varie- 
ties are  almost  innumerable.  From  those  grown  in  Southern  Europe 
wines  and  raisins  are  made,  the  latter  being  merely  the  sun-dried 
grapes. 

In  the  United  States  the  Old  World  Vine  is  grown  in  the  Southern 
and  Pacific  Coast  States,  and  in  the  latter  region  fine  raisins  are  madi-. 
In  other  portions  of  this  country  only  the  native  species  are  grown,  viz.  : 

V.  Labrmca,  the  Northern  Fox  Grape  ;  from  this  have  originated 
most  of  the  common  varieties,  as  Catawba,  Concord,  Isabella,  etc. 

V.  CBstivalis,  the  Summer  Grape,  from  which  we  have  obtained  the 
Virginia  Seedling,  Herbemont,  etc. 

V.  riparia,  the  River-bank  Grape,  which  has  produced  the  Taylor 
Bullit,  Delaware,  and  Clinton, 


two  are  fully  dev 

^hvaed  one^repret 
dots.—  After  Sachs. 


loped, 


538 


BOTANY. 


V.  vulpina,  the  Southern  Fox  Grape,  which  has  given  rise  to  the 
Scuppernong  and  other  varieties.* 

From  these  American  grapes  excellent  wines  are  now  made  ;  but  no 
raisins  have  yet  been  made  from  them. 

The  Virginia  Creeper,  Ampelopsis  quinquefolia  (or  Vitis  quinquefolia), 

Fias.  494-501.— ILLUSTRATIONS  OF  VITIS  VINIFERA. 


FIG.  497. 


FIG.  498. 


FIG.  499. 


FIG.  500. 


FIG.  501. 


Fig.  494,-Flower  bud.    Magnified. 

Fig.  495,-Section  of  flower-bud.    Magnified. 

Fig.  496.— Flower  without  corolla.    Magnified. 

Fi£.  497.— Flower  diagram.  Fig.  498  —Fruit. 

Fig.  499. -Seed.     Magnified.  Fig.  500.— Cross-section  of  seed.    Magnified. 

Fig  501.— Vertical  section  of  seed.    Magnified. 

is  one  of  our  finest  native  ornamental  climbers. 

Javan  and  Sumatran  species  of  Vitis,  formerly  referred  to  Cissus,  are 
common  in  conservatories. 

Order  Rhamnaceae. — Trees  and  shrubs,  often  spinescent.  bearing- 
simple,  usually  alternate  leaves  ;  flowers  with  valvate  calyx  lobes. 
Species  430.  Inhabitants  for  the  most  part  of  warm  and  temperate 
regions.  Many  possess  a  purgative  principle. 


*  This  distribution  of  the  cultivated  varieties  is  that  made  by  Dr 
Ueorge  Engelinan.     American  Naturalist,  1872,  p.  539. 


OLACALES.  539 

The  fruits  of  some  species  of  Rhamnm  yield  yellow  or  green  dyes, 
which  are  of  considerable  importance. 

The  wood  of  R.  frangula,  of  Europe,  is  used  for  making  the  best 
charcoal  for  tlie  finest  gunpowder. 

Species  of  Zizyphus  in  Africa  and  India  produce  edible  fruits,  one  of 
which  is  the  Jujube. 

Rhamnus  catharticus,  the  Buckthorn  of  Europe,  is  planted  in  this 
country  for  hedges. 

Order  Stackhousieae. — Small  herbs,  mostly  confined  to  Australia. 

Order  Celastracese. — Small  trees  and  shrubs,  often  climbing,  bear- 
ing simple,  usually  alternate  leaves;  flowers  with  imbricate  calyx 
lobes.  Species  about  400,  natives  of  temperate  and  tropical  regions. 

Celastrus  scandens,  the  Climbing  Bittersweet  of  the  Eastern  United 
States,  is  ornamental,  and  is  planted  in  this  country  and  Europe. 

Euonymus  atropurpureus,  the  Waahoo,  or  Burning  Bush  of  the 
Eastern  United  States,  is  also  found  in  gardens. 

The  wood  of  E.  Europeans  of  Europe  is  compact  and  capable  of 
being  split  into  very  fine  pieces,  and  is  used  by  watch-makers  under 
the  name  of  Dogwood.  It  is  also  used  for  skewers,  shoe-pegs,  etc. 

From  the  leaves  of  Catha  edulis,  an  East  African  shrub,  a  decoction  is 
made  which  produces  an  agreeable  excitement.  The  leaves  themselves 
are  sometimes  chewed. 

597.— Cohort  XXIX.  Olacales.  Flowers  actinomorphic ; 
ovary  superior,  entire,  one-  to  many-celled;  seeds  with  copious 
endosperm. 

Order  Cyrillacese.— Trees  and  shrubs,  numbering  eight  species, 
represented  in  the  Southern  United  States  by  CyriUa  racemiflora,  the 
Ironwood,  and  Gliftonia  ligustrina,  the  Buckwheat  Tree,  the  latter  a 
handsome  evergreen  tree,  three  to  six  metres  high  (10  to  20  feet). 

Order  Ilicineae.— The  Holly  Family.  Trees  and  shrubs  with  mostly 
evergreen  leaves,  and  three-  to  many-celled  ovary.  Species  150,  of 
tropical  and  temperate  climates. 

Ilex  Aquifulium,  the  Holly  Tree  of  Europe,  yields  a  white  close- 
grained  wood  much  esteemed  by  turners  and  cabinet-makers.  It  is 
sometimes  blackened  so  as  to  resemble  ebony.  The  tree,  being  orna- 
mental, is  extensively  planted.  The  bright  red  berries  remain  during 
the  winter,  and  with  the  evergreen  foliage  are  used  for  Christmas 
decorations. 

/.  opaca,  the  American  Holly,  of  the  Southern  States  and  the  Atlan- 
tic coast  from  Massachusetts  southward,  resembles  the  preceding  and 
is  used  for  the  same  purposes.  This  and  other  native  species  are  culti- 
vated in  gardens. 

The  leaves  of  /.  Paraguayensis,  a  small  South  American  tree,  furnish 


540  BOTANY. 

the  Paraguay  tea,  sometimes  called  Mate.  It  contains  Caffeine,  the 
active  principle  in  tea  and  coffee. 

Order  Olacinese.— Trees  and  shrubs,  about  170  species,  almost  en- 
tirely of  the  tropics. 

598.— Cohort  XXX.  G-eraniales.  Flowers  often  zygo- 
morphic  ;  ovary  superior,  entire,  lobed,  or  sub-apocarpous. 

Order  Chailletiaceae. — Tropical  shrubs  and  trees. 

Order  Meliacese.— Trees  (rarely  undershrubs),with  mostly  pinnately 
compound  leaves ;  stamens  united  into  a  tube  ;  ovary  entire.  Species, 
270,  nearly  confined  to  the  tropics. 

Several  trees  yield  valuable  timber. 

Melia  Azedarach,  the  Pride  of  India  Tree,  indigenous  throughout 
Western  Asia,  now  naturalized  in  all  the  Mediterranean  region,  and 
the  Southern  United  States,  is  a  fine  tree,  whose  reddish  wood  is  sus- 
ceptible of  a  beautiful  finish. 

Swietenia  Mahogoni.  a  native  of  tropical  America  (barely  reaching 
South  Florida),  yields  the  well-known  Mahogany  wood.  The  trees 
are  of  great  thickness,  sometimes  being  as  much  as  two  metres  in 
diameter. 

Cedrel'a  odorata,  of  Jamaica,  yields  Jamaica  Cedar. 

C.  Toona,  of  India,  produces  Chittagong  wood. 

C.  australis,  an  immense  Australian  species,  resembles  the  Jam«ica 
Cedar.  The  wood  of  the  three  foiegoing  species  of  Cedrella  is  fine 
grained,  and  well  adapted  to  many  uses. 

Chloroxylon  Swietenia,  of  Ceylon  and  Western  India,  is  a  large  tree, 
whose  fine-grained  satin-like  wood,  called  Satin  Wood,  is  much  prized 
in  cabinet  and  furniture  making  and  fine  turnery. 

Order  Burseraceee. — Trees  and  shrubs,  abounding  in  resinous  or 
oily  secretions  ;  species,  145,  nearly  all  tropical. 

Balisamodendron  Myrrha  and  B.  Katnf,  small  Arabian  trees,  yield 
Myrrh. 

B.  Africanum,  of  Eastern  Africa,  produces  African  Bdellium. 

Olibanum,  an  incense  resin,  is  obtained  from  Boswellia  thurifera,  a 
lofty  tree  of  Central  India. 

Buraera  gummifera,  West,  Indian  Birch,  of  South  Florida  and  the 
West  Indies,  yields  a  gum  resin  called  Chibou  or  Cachibou. 

Order  Ochnaceee.— Tropical  shrubs  and  trees  with  a  watery  juice. 

Order  Simarubaceee.— Shrubs  and  trees,  with  scentless  foliage  ; 
leaves  generally  compound  and  alternate  ;  stamens  distinct.  About 
112  species,  almost  confined  to  the  tropics,  are  known.  The  bitter  bark 
and  wood  of  many  species  are  made  use  of  in  medicine.  That  from 
Quassia  amara,  a  small  tree  of  tropical  America,  is  the  Quassia  of 
pharmacy.  From  a  West  Indian  tree,  Simnruba  umara,  the  drug 
Simarulw  Bark  is  obtained. 


a  ERA  NT  ALES. 


541 


AHanthua  glandulosus,  the  Tree  of  Heaven,  a  native  of  China,  is  com- 
monly planted  in  the  United  States  as  a  shade  tree.  Its  wood  is  valu- 
able in  cabinet-making. 

Order  Rutacese. — The  Rue  Family.  Shrubs  and  trees,  rarely  herbs, 
with  glandular-punctate  heavy-scented  foliage  ;  leaves  generally  com- 
pound and  alternate;  stamens  generally  distinct.  The  order  as  here 
considered  includes  650  known  species,  widely  distributed  in  tropical 

FIGS.  508-505.— ILLUSTRATIONS  or  CITRUS  AUHANTIUM. 


FIG.  504.  Fio.  505. 

Fig.  502. -Section  of  flower.    Magnified. 
Fig.  BOS.— Part  of  androacium.    Magnified. 
Fig.  504. -Flower  diagram. 
Fig.  505. -Calyx  and  ovary.    Magnified. 

and  temperate  climates.     Seven  tribes,  most  of  which  were  former!/ 
considered  to  be  orders,  are  recognized  by  Bentham  and  Hooker. 

Tribe  Aurantiece,  with  actinomorphic,  monoclinous  flowers, 
baccate  (berry-like)  fruits,  and  seeds  without  endosperm.  (Figs.  502-5.) 

Citrus  Aurantium,  the  Sweet  Orange,  is  an  Indian  tree,  now  grown 
throughout  all  warm  countries  of  the  world  for  its  well-known  fruits. 

G.  Limonum,  the  Lemon,  is  a  native  of  Northern  India,  now  widely 
distributed.  It  was  introduced  into  Europe  during  the  Crusades. 

Other  species  of  Citrus  yield  valuable  fruits,  as  C.  medtca,  the  Citron  ; 
C.  Limetta,  the  Lime  ;  C.  decumana,  the  Shaddock  ;  C.  Bigaradia,  the 
Seville  or  Bitter  Orange,  etc.,  etc. 

The  hard  yellow  wood  of  the  Orange  is  valued  for  inlaying 


542  SOTANT. 

Tribe  Tod<hfliece,  with  actinomorpliic,  mostly  diclinous  flowers, 
coriaceous  or  baccate  fruits,  and  seeds  with  endosperm. 

Ptdea  trifolifita,  the  Hop  Tree,  of  the  Eastern  United  States,  Skim- 
mia  Japonica,  a  small  Japanese  shrub,  and  two  species  of  PheUoden- 
dron,  from  Manchuria,  are  planted  in  gardens. 

Tribe  Xantltoxylew,  with  actinomorphic,  mostly  diclinous 
flowers,  usually  capsular  fruits,  and  seeds  mostly  with  endosperm. 

Xanthoxylum  Americanum,  the  Common  Prickly  Ash,  of  the 
Northern  United  Slates,  and  X.  Clava-Herculis,  the  Southern  Prickly 
Ash,  of  the  Southern  States,  are  ornamental  shrubs,  and  are  often 
planted. 

Tribe  Soroniece. — Australian  shrubs. 

Tribe  Diosmea?,  with  actinomorphic,  monoclinous  flowers,  cap- 
Hiilar  fruits,  and  seeds  without  endosperm. 

Species  of  Diosma  and  Barosma,  pretty  African  shrubs,  are  to  be  found 
in  conservatories.  From  their  leaves  the  drug 
Buchu  is  obtained. 

Tribe  Rutece,  with  generally  actinomorphic, 
monoclinous  flowers,  capsular  fruits,  and  seeds 
with  endosperm.  (Fig.  506.) 

Ruta  graveolens,  the  Common  Rue  of  the  gar- 
dens, is  a  native  of  Southern  Europe  and  West- 
ern Asin. 

___.  Dictamnus  Fraxinetta,  Fraxinella,  or  the  Gas 

r  of  Dictamnvs   Plant,     is   a    heavy-scented    ornamental    plant, 
ni  $  &rati-   wLose  glandular  foliage  secretes  a  volatile  oil, 
gin>  slightly  shaded.— Af-   which    is    said    sometimes   to   flash   into  flame 
when  a  light  is  brought  near  to  it,  (Figs.  116-7.) 

Tribe  Cuspariece,  with  zygomorphic,  monoclinous  flowers,  cap- 
sular fruits,  and  seeds  without  endosperm. 

Galipea  cusparia,  a  large  tree  of  Guiana  and  Brazil,  furnishes  a  bit- 
ter medicinal  bark,  known  as  Angustura  Bark. 

Order  Geraniaceee. — The  Geranium  Family.  Mostly  herbs  (rarely 
shrubby  or  arborescent) ;  leaves  opposite  or  alternate,  simple  or  com- 
pound ;  stamens  more  or  less  united  below  ;  species,  750,  mostly  of 
temperate  and  sub-tropical  climates. 

Many  are  cultivated  as  ornaments. 

Tmpatiens  Balsamina,  the  Garden  Balsam,  or  Touch-Me-Not,  some- 
times erroneously  called  "  Lady's  Slipper,"  is  a  well-known  annual 
from  India,  which  has  been  cultivated  for  more  than  two  hundred  and 
fifty  years.  The  name  Touch-Me-Not  (referring  to  its  e'nsticnlly  open- 
ing fruits)  is  shared  by  two  pretty  native  species.  (Fi>r.  507.) 

Oxalis  contains  several  native  species  of  Wood  Sorrel,  all  of  which 


GERANIALES. 


543 


are  pretty,  and  many  exotic  species  (mostly  South  African),  which  are 
in  common  cultivation. 

TropcBolum  majus,  the  Nasturtium,  from  South  America,  is  in  com- 
mon cultivation.  The  edible  tuberous  roots  of  T.  tuberosum,  of  Peru, 
are  used  instead  of  potatoes  in  some  parts  of  South  America. 

Pelargonium  is  another  South  African  genus,  which  has  furnished 
us  with  many  fine  greenhouse  and  garden  flowering  plants,  most  of 
which  are  erroneously  called  Geraniums. 

The  true  Geraniums  belong  to  the  genus  of  that  name  represented  in 
this  country  by  eight  or  nine  wild  species. 

Erodium  ciciitarium,  the  Alfilaria,  of  California,  "  is  a  valuable  and 
nutritious  forage  plant  reputed  to  impart  an  excellent  flavor  to  milk 
and  butter."  (Brewer.) 

Order  Zygophyll- 
aceee.— Shrubs  and  herbs 
(a  few  trees),  with  oppo- 
site compound  leaves  ; 
stamens  distinct ;  spe- 
cies, about  100,  almost 
confined  to  the  tropics. 

Guaiacum  ojftcinale, 
the  Lignum-vitae,  of  the 
West  Indies,  is  a  tree 
six  to  nine  metres  (20  to 
30  feet)  high,  whose  dark 
red,  almost  black,  heart- 
wood  is  exceedingly 
hard ;  it  furnishes  the 
best  material  for  ship's 
blocks,  pulleys,  etc. 

Larrea,  Mexicana,  the 
Creosote  Bush  of  Arizona,  is  a  curious  diffusely  branched  evergreen 
shrub,  with  a  very  strong  creosote-like  odor. 

Order  Malpighiaceee,— Trees  and  shrubs,  often  climbing  ;  natives 
for  the  most  part  of  the  tropics;  species,  580,  some  of  which  are  culti- 
vated in  greenhouses. 

Order  Humiriacese.— Balsamic  trees  and  shrubs  of  tropical  America 
and  Africa. 

Order  Linaceee.— The  Flax  Family.  Herbs,  shrubs,  and  a  few  trees, 
with  alternate  or  opposite  simple  leaves  ;  stamens  more  or  less  united 
below ;  species,  135,  widely  distributed  in  temperate  and  tropical 
climates. 

The  most  important  plant  of  the  order,  and  one  of  the  most  impor- 
tant in  the  vegetable  kingdom,  is  the  Flax,  Linum  iisitatimmum,  cul- 
tivated from  time  immemorial  for  its  fibres,  called  linen  (the  bast  fib'es 


Fig.  507.— A,  the  fruit  of  Impatiens  Bahamina.  S, 
the  same  after  dehiscence  ;  a,  a,  carpels  ;  gr,  seeds. 
—After  Duchartre. 


BOTANY. 


of  the  cortical  part  of  the  stem).  The  mummy  cloth  of  ancient  Egypt 
is  composed  of  flax  fibres,  and  in  the  remains  of  tin-  "  lake  dwellings" 
in  Switzerland,  fragments  of  linen  cloth  have  been  found.  The  plant 
appears  to  be  indigenous  in  the  south  of  Europe,  as  well  as  in  the 
regions  eastward  in  Asia  ;  it  is  now  cultivated  throughout  the  North 
and  South  Temperate  Zones.  The  seeds  are  rich  in  oil,  which  is 
extracted  by  pressure,  producing  the  Linseed-oil  of  commerce ;  the 

FIGS.  508-10.— ILLUSTRATIONS  OF  LINITM  USITATISSIMUM. 


Fio.  508. 


Fig.  ."08.  —  Inflorescence. 
Fig.  510.— Diagram  of  flower. 


FIG.  510. 
Pig.  509.— Section  of  flower. 


Mimnitird. 


compressed  refuse  in  called  oil-cake,  and  is  much  used  as  food  for 
cattle.  (Fign.  508-10.) 

Erythroxylon  Coca,  a  South  American  shrub,  is  cultivated  in 
Bolivia  and  New  Granada  for  its  stimulating  leaves,  which  are  chewed 
like  tobacco. 

599.— Cohort  XXXI.  Malvales.  Flowers  usually  actino- 
morphic  ;  stamens  indefinite,  generally  monadelphous  ;  ovary 


MALVALK8. 


superior,  generally  three-  to  many-celled  ;  seeds  mostly  with 
endosperm. 

Order  Tiliacese.— The  Linden  Family.     Trees  and  slirubs  (a  few 
herbs),  with  mostly  alternate  simple  leaves ;  stamens  distinct,  or  some- 
what united  below.     Species 
330,  mostly  tropical.  F'«8-  5n-™-^%™«>  °*  THEOBR°- 

Tilia  Europaa,  the  Lime 
or  Linden  Tree  of  Europe 
and  Siberia,  is  a  large  and 
valuable  tree,  yielding  a  soft 
white  wood  much  esteemed 
by  carvers,  musical  instru- 
ment makers,  and  others. 
The  fibre  of  its  bark  is  used 
for  making  coarse  mats,  and 
its  flowers  produce  a  great 
quantity  of  most  excellent 
honey. 

T.  Americana,  the  Amer- 
ican Linden,  Linn,  or  Bass- 
wood  of  the  Eastern  United 
States,  resembles  the  preced- 
ing, and  is  equally  valuable. 

While  the  wood  of  our  rep- 
resentatives of  the  order  is 
soft,  that  of  some  tropical 
species  is  very  hard  —  e.g., 
Sloanea  dentata,  a  West  In- 
dian tree,  which  has  received 
the  significant  name  of 
Break- Ax  Tree. 

Corchorus  capsularis,  a  tall- 
growing  annual  of  India, 
yields  the  Jute  fibre  now  ex- 
tensively used  in  making 
gunny  bags,  coarse  carpets, 
ii nd  even  fabrics  of  consider- 
able fineness. 

Order  Sterculiaceee.  — 
Trees  and  shrubs  (a  few 
herbs)  with  alternate  simple 

or  compound  leaves  ;  stamens  more  or  less  united  into  a  tube. 
520  species  contained  in  this  order  are  almost  entirely  tropical. 

Theobroma  Cacao,  the  Chocolate  Tree  of  tropical  America,  attains  a 
height  of  five  to  six  metres  (16  to  20  ft.),  and   bears  elongated  ribbed 


Fie.  B13. 


FIG.  511. 

Fig.  511.— Fruit  %  natural  size). 

Fisr.  512.— Seed.    Magnified. 

Fig.  513,-Seed  cut  vertically.    Magnified. 


The 


546 


BOTA  NY. 


fleshy  fruits,  each  containing  fifty  or  more  oily  seeds  (Figs.  511-13). 
The  seeds  are  roasted  and  then  ground,  and  made  into  a  paste  and  dried, 
constituting  the  Chocolate  or  Cocoa  of  commerce,  according  as  vanilla, 
sugar,  and  other  substances  are,  or  are  not  added.  Chocolate  and  Co- 
coa contain  TJieobromine  (C7  H8  N4  O2),  an  alkaloid  similar  to  Caffeine. 
Order  Malvaceae.—  The  Mallow  Family.  Herbs,  shrubs,  and  trees, 
with  alternate  simple  leaves  ;  stamens  indefinite,  united  into  a  tube  ; 


FIGS.  514-19.  —  IIXUSTBATIOMS  OP  MALVACE.*;  (Malva  sylvestris). 


FIG.  517. 


FIG.  518. 


Magnified.    Fig.  515.— Androecium.    Magnified. 
Magnified.  Fig.  517. -Calyx  and  pistil.    Magnified. 

Fig.  518. -Flower  diagram.  Fig.  519.-Fruit: 


Fig.  514.— Section  of  flower. 
Fig.  51 6. -Stamen.    "m 


anthers  one-celled.     Species  about  700,  widely  distributed,  but  most 
abundant  in  tropical  regions.     (Figs.  514-19.) 

Oosxypium  herbaceum,  the  common  Cotton  Plant  of  tropical  and  sub- 
tropical countries,  was  probably  derived  originally  from  some  part  of 
India.  Its  culture  by  the  East  Indians  and  Egyptians  was  known 
many  centuries  before  the  Christian  era.  In  England  the  manufacture 
and  use  of  cotton  cloth  began  during  the  latter  part  of  the  sixteenth 


G  UTTIFEBALES. 


54? 


century.  The  culture  ol  cotton  in  North  America  dates  from  almost 
the  first  settlements  in  the  Southern  States,  and  the  cotton  crop  is  now 
more  valuable  than  the  product  of  any  other  single  cultivated  plant  in 
the  United  States.  It  is  extensively  cultivated  in  the  West  Indies, 
Brazil,  Egypt,  and  India. 

The  fibre  of  cotton  consists  of  greatly  elongated  hairs  (trichomes), 
which  develop  in  great  numbers  upon  the  outer  surface  of  the  seed- 
coats  ;  these  are  at  first  cylindrical,  but  upon  drying,  as  the  seed-pod 
approaches  maturity,  they  collapse  and  appear  flat  and  more  or  less 
bent  and  twisted. 

Some  East  and  West  Indian  trees  of  the  genus  Bombax  produce  an 
abundance  of  a  similar  fibre,  which  is  fine  and  silky,  hence  the  trees 
are  known  as  Silk  Trees.  It  is  said,  however,  that  the  fibre  cannot  be 
woven,  and  it  is  at  present  only  used  for  stuffing  cushions,  etc. 

The  bast  fibres  of  the  stems  of  some  species  are  useful.  Species  of 
Sida  in  India,  China,  and  Australia,  of  Plagianthus  in  New  Zealand, 
and  of  Thespesia  and  Hibiscus  in  tropical 
America,  are  thus  used  ;  from  the  last  the 
fibre  called  Cuba  Bast  is  obtained. 

Hibiscus  esculentus,  the  Okra  or  Gumbo 
of  tropical  America,  produces  mucilaginous 
edible  pods,  which  are  much  used  in  the 
Southern  United  States. 

Species  of  Durio  in  the  Malay  Archipel- 
ago, and  of  Matisia  in  New  Granada,  fur- 
nish  the  inhabitants  of  those  countries  with 
valuable  fruits.  The  wood  of  most  of  the 
species  of  the  order  is  very  soft  and  com- 
pressible  ;  this  is  particularly  the  case  with 
a  West  Indian  tree,  Ochroma  Lagopus,  whose  wood,  known  as  Cork 
Wood,  has  been  used  as  a  substitute  for  cork. 

The  Baobab  Tree  of  tropical  Africa  is  remarkable  for  the  enormous 
size  of  its  rounded  spreading  top  and  the  thickness  of  its  short  stem. 

Among  the  more  common  ornamental  plants  of  the  order  are  Mallows 
(Maloa),  Rose  Mallow  (Hibisciis),  Hollyhock  (Althaea),  GaUirhoe,  etc. 

600.— Cohort  XXXII.  Guttiferales.  Flowers  actino- 
morphic  ;  stamens  indefinite  ;  ovary  superior,  three-  to  many- 
celled. 

Order  Chlaenacese. — A  few  shrubs  and  trees  of  Madagascar. 

Order  "Dipterocarpese. — Tropical  trees  (rarely  shrubs),  about  112  in 
number,  the  most  important  of  which  is  Drydbalanops  CampTiora,  the 
Kapor  or  Camphor  Tree  of  Borneo  and  Sumatra,  which  attains  a  height 
of  forty  metres  (130  ft.),  and  yields  a  hard  red  timber  used  in  boat- 
building. Its  resin  is  called  Sumatra  Camphor,  and  is  much  used  in 
China  and  Japan. 


548 


BOTANY. 


FIGS.  521-5.— ILLUSTRATIONS  OP  CA 
LIA  CHINENSIS. 


Order  Ternstrcemiaceee.— Trees  and  shrubs  with  alternate  (rarely 

opposite)  leaves,  and  mostly  monoclinous  axillary  or  racemed  flowers. 

Species  260,  mostly  tropical.     (Figs.  520  and  521-5.) 

Several  ornamental  species  are  indigenous  to  the  Southern  United 

States— e.g.,  the  Loblolly  Bay  (Gordonia  Lasianthus,  Fig  520),  a  tree 

nine  to  fifteen  metres  (30  to  50  ft.)  high  ;  O.  pubtscens,  the  Mountain 

Bay  ;  and  two  shrubby  species  of  Stuartia. 
The   most   common   exotic  species  cultivated  for  ornament  is  the 

Camellia  (Camellia  Japonicu)  a   well-known    hot-house  shrub    from 

China  and  Japan. 

The  Tea  Tree  (Camellia  Chinemis  or  Thea  Chinensis)  is  an  evergreen 
tree  three  to  five  metres  high,  and 
a  native,  probably,  of  Southern 
and  Eastern  Asia.  It  has  been 
cultivated  for  ages  by  the  Chi- 
nese, and  has  lately  been  intro- 
duced to  a  limited  extent  into 
other  countries.  In  preparing  the 
leaves  they  are  carefully  picked, 
and  then  are  subjected  to  alternate 
drying,  pressing,  rolling  and  air- 
ing until  the  proper  chemical 
changes  have  taken  place,  and  a 
sufficient  part  of  the  water  is 
driven  off.  The  different  kinds 
and  qualities  of  tea  depend  upon 
the  rapidity  of  the  process,  and 
also  upon  the  age  of  the  leaves 
used,  the  more  rapid  process  and 
the  younger  leaves  producing  the 
finer  green  teas,  the  slower  pro- 
cess and  older  leaves  producing 
the  black  teas.  Somewhat  appears 
also  to  depend  upon  the  variety  of 

niflei.  525--Halfembr^°'innulface-  M«S-    the  plant,  there  being,  it  is  gene- 
rally  admitted,  two    varieties  or 

races,  viz.,  var.  viridw  aud  var.  Bohea. 

Tea  leaves  after  preparation  contain  the  alkaloid  Caffeine  (C8  Hl() 

N4  Oa  +  H3  O),  which  also  occurs  in  roasted  coffee. 
Order  Guttifereee.—  Trees  and  shrubs  with  yellowish  or  greenish 

resinous  juice,  opposite  leaves,  and  mostly  diclinous  flowers.     Species 

230,  all  tropical. 

Gurdnia  MoreUa,  a  small  tree  of  Siam,  produces  Gamboge,  a  valuable 

color  used  in  painting.     Incisions  are  made  into  the  bark,  and  the  juice 

which  exudes  is  gathered  and  dried,  constituting  the  crude  UamUoge. 
The  Mangosteen,  a  fruit  about  as  large  as  an  apple,  and  considered 


FIG.  523. 


Fig.  521.-Ripe  fruit.     Ms 

Fijr.  522.— Seed.    Magnified. 

Fie.  523.—  Section  of  seed     Magnified 

Fig.  524.— Embryo.    Magnified. 


CARYOP1IYLLALES.  549 

to  be  one  of  the  most  delicious  of  all  fruits,  is  produced  by  Garcinia 
Mangostana,  a  small  tree  of  the  Moluccas. 

The  fruit  of  Mammea  Americana,  a  tall  West  Indian  tree,  is  kno.va 
as  the  Mammee  Apple.  It  is  as  large  as  a  melon,  and  its  yellow  pulp 
is  said  to  be  delicious. 

A  Central  American  species  of  Calophyllum  yields  a  pale  reddish,  very 
durable  timber  known  as  Santa  Maria  wood. 

Order  Hypericaceee. — Herbs  and  shrubs  (a  few  trees)  with  opposite 
glandular-punctate  leaves,  and  monoclinaus  flowers.  Stamens  united 
into  three  or  five  bundles  (Fig.  526).  Species  210, 
mostly  found  in  temperate  climates. 

Our  species  are  all   herbs  or  low  shrubs,  be- 
longing to  the  genera  Hypericum  and  Ascyrum. 

A  species  of  Cratoxylon,  in  tropical  India,  is  a 
large  tree  with  dark  brown  wood. 

Order  Elatinaceae. — Containing  a  few  marsh 
plants. 

601.— Cohort    XXXIII.     Caryophyll-      Fig-  526.— Diagram  of 

,  -rn  ,  .  the    flower   of    Hyperi- 

ales.      1  lowers   actmomorphic  ;    stamens  cum  eaiyctnum.— After 
generally   definite,    usually   as    many    or 
twice  as  many  as  the  petals  ;  ovary  superior,  one-celled  ;  pla- 
centa usually  central  and  free  ;  seeds  with  endosperm. 

Order  Tamariscinese. — Mostly  shrubs  of  the  Old  World,  with  mi- 
nute alternate  simple  leaves. 

Of  the  forty  species,  but  three  are  found  in  the  New  World,  and  all 
these  reach  our  extreme  Southwestern  border. 

Tamarix  Gallica,  the  Tamarisk  of  Europe  to  India,  is  a  common 
ornamental  shrub  in  this  country. 

Order  Portulacacese.— Herbs  and  a  few  small  shrubs,  with  alter- 
nate or  opposite  leaves  ;  sepals  generally  two.  Species  125,  widely  dis- 
tributed, but  most  abundant  in  the  New  World. 

Portulaca  oleracea,  the  common  Purslane,  is  an  East  Indian,  or  possi- 
bly South  European  weed.  It  was  formerly  used  as  a  pot  herb. 

P.  grandiflora,  the  Portulaca  of  the  gardens,  is  a  pretty  flowering 
annual. 

Claytonia  and  Calandrinin,  which  have  many  native  representatives, 
are  ornamental. 

Order-  Caryophyllaceae.— The  Pink  Family.  Mostly  herbs  with 
opposite  leaves  ;  sepals  four  or  five,  free  or  united  into  a  tube  ;  placenta 
central.  Species  800,  distributed  throughout  the  world,  but  most 
abundant  in  Arctic,  Alpine,  European,  and  Western  Asiatic  coun- 
tries. 


550 


BOTANY. 


Aside  from  the  ornamental  species  and  the  weeds,  the  order  possesses 
no  plants  of  much  economic  importance. 

The  roots  of  tiapoi<aria  ojfidnalis  contain  Saponin,  and  are  detergent, 
but  not  sufficiently  so  to  be  much  used. 

Among  the  ornamental  plants  are  the  Carnations  and  Clove  Pinks 
(Dianthus  sp.),  the  Mullein  Pink  (Lychnis),  Catcbfly  (Silei  e),  Bouncing 
Bet  (Saponaria),  Gypsophila,  etc. 

Among  the  weeds  are  species  of  Ceiastium  (Fig.  527),  Spergula,  and 

the  Corn  Cockle, 
Lychnis  Oithago. 
The  latter  is  often 
quite  abundant  in 
wheat  fields,  to  the 
great  detriment  of 
the  flour  manufac- 
tured from  the 
wheat. 

Order  Franken- 
iaceee. —  M  ari- 
time  herbs  and 
low  shrubs  resem- 
bling Caryophyll- 
acese,  but  with  par- 
ietal placentae. 

602.  — Cohort 
XXXIV.  Poly- 
galales.  Flow- 
ers actinomorph- 
icorzygomorph- 
ic ;  stamens  defi- 
nite, as  many 
as  or  twice  as 


maryaxis ;  t',  secondary  axes  ;  t",  tertiary  axes  ;   <"','qua-    manj  as  the  pet- 


Fig.  527.—  lu florescence  of  Cerastium  cottinum. 
lary  axis  ;  <',  secondary  axes  ;  t",  tertiary  axes  ;  I 
ternary  axes  ;  t"",  quinary  axes.— After  Duchartre.  u]g  •  ovai'V  ttSUal- 

ly  two-celled  ;  seeds  mostly  with  endosperm. 

Order  Vochysiacese. — Trees  with  a  resinous  juice,  and  opposite  or 
verticillate  leaves  ;  flowers  zygomorphic.  Species  about  100,  confined 
to  tropical  America. 

Vochysia  Quianensis,  of  Guiana,  furnishes  the  Copai-ye  Wood,  there 
used  for  making  boat-oars,  the  staves  for  sugar  hogsheads,  etc. 

Order  Polygalaceee.— Mostly  herbs  with  alternate  leaves  ;  flowers 
zygomorphic.  Species  400,  distributed  throughout  temperate  and 
tropical  countries. 


PARIETALES.  551 

A  bitter  principle,  which  is  sometimes  emetic  and  purgative,  per- 
vades the  order. 

Some  South  African  species  of  PolygaZa  are  grown  as  ornamental 
plants  in  conservatories.  A  few  have  a  little  reputation  as  medicines. 

Order  Tremandreee,  containing  a  few  Australian  shrublets. 

Order  Pittosporaceee. — Trees  and  shrubs  with  alternate  leaves, 
and  actinomorphic  flowers ;  petals  cohering  into  a  tube.  Species 
ninety,  of  Africa,  India,  China,  and  Australia. 

Pittosporum  Tobira  is  a  common  plant  in  conservatories. 

P.  undulatum.oi  Australia,  attains  a  height  of  twenty  to  twenty-five 
metres  (70  to  80  ft.),  and  its  wood  resembles  Boxwood. 

Climbing  species  of  Sollya  and  other  genera  are  grown  in  green- 
houses. 

6O3.— Cohort  XXXV.  Parietales.  Flowers  actinomorph- 
ic or  zygomorphic ;  stamens  definite  or  indefinite ;  ovary 
usually  one-celled,  with  parietal  placentae. 

Order  Bixineee.— Trees  and  shrubs  with  alternate  simple  leaves, 
actinomorphic  flowers,  and  generally  indefinite  stamens ;  seeds  with 
endosperm.  Species  160,  mostly  tropical. 

One  or  two  species  of  Amoreuxia  barely  reach  our  extreme  South- 
western border. 

Bixia  Orellana,  a  small  South  American  tree  now  cultivated  in  many 
tropical  countries,  produces  fruits  whose  orange-red  pulp  when  pre- 
pared and  dried  is  the  valuable  dye  known  as  Arnotto. 

The  fruits  of  some  species  are  eaten,  and  a  few  gums  are  derived 
from  others. 

Order  Canellacese,  containing  four  or  five  species  of  tropical  trees. 

Canella  alba  yields  Canella  Bark,  which  is  used  in  medicine. 

Order  Violaceee. — The  Violet  Family.  Herbs  and  shrubs  with 
mostly  .alternate  leaves,  zygomorphic  flowers,  and  definite  stamens; 
seeds  with  endosperm.  Species  240,  widely  distributed  in  temperate 
and  tropical  regions. 

An  emetic  and  laxative  principle  is  common  in  the  plants  of  this 
order. 

The  genus  Viola,  the  Violets,  includes  about  half  of  the  species  of 
the  order  ;  many  of  these  are  indigenous  to  parts  of  the  United  States, 
and  nearly  all  of  these,  as  well  as  the  exotic  species,  are  ornamental. 

V.  odorata,  the  Sweet  Violet,  and  V.  tricolor,  the  Pansy,  both  natives 
of  Europe,  are  common  in  gardens  and  door-yards.  Of  the  latter  there 
are  almost  numberless  varieties. 

Several  Brazilian  shrubby  plants  of  the  order  are  cultivated  in  green- 
houses. 

The  root  of  lonidium  IpecacuanM,  a  Brazilian  shrub,  is  the  White 
Ipecacuanha  of  pharmacy. 


552 


BOTANY. 


A  Peruvian  tree,  Leonid  glycycarpa,  produces  edible  pulpy  fruits  as 
large  as  a  peach. 

Order  Cistaceee. — Herbs  and  shrubs  with  actinomorphic  flowers. 
Species  about  sixty,  mostly  of  temperate  climates. 

A  shrubby  Cistus  from  the  South  of  Europe  is  common  in  green- 
houses. 

Some  of  our  native  species  of  Frostweed  (Helianthemum)  and  Hud- 
sonia  are  pretty. 

Order  Resedacese. — Herbs  (a  few  shrubs)  with  alternate  leaves, 
mostly  zygomorphic  flowers,  indefinite  stamens,  and  seeds  without 
endosperm.  Species  twenty  to  twenty-five,  confined  to  the  Mediter- 
ranean region  and  South  Africa,  with  the  exception  of  two  or  three  spe- 

FIGS.  528-30. — ILLUSTRATIONS  o»  CBUCIPEB^E  (WALLFLOWER). 


Fie.  528. 


FIG.  530. 


FIG.  529. 


Fig.  528.— Flowpr  diagram.  Fig.  529.— Section  of  Flower.    Magnified. 

Fig.  530.— Andrcecium.    Magnified. 

cies  which  reach  India,  one  of  wbich  (Oligomeris  subulata)  extends  to 
California. 

Reseda  odorata  is  the  well-known  Mignonette,  probably  a  native  of 
the  Eastern  Mediterranean  region. 

The  foliage  of  R.  luteola,  an  annual  of  Europe  called  Dyers'  Weed 
or  Weld,  furnishes  an  important  yellow  dye. 

Order  Capparidaceae.— Htrbs,  shrubs  and  trees  with  mostly  alter- 
nate leaves,  actinomorphic  flowers,  mostly  indefinite  (never  tetradyna- 
mous)  stamens,  and  seeds  without  endosperm.  Species  300,  mostly 
tropical  or  sub-tropical.  An  acrid  volatile  principle  prevails  in  the 
order. 

Capparis  vpinosa,  a  stiff  prickly- branched  shrub  of  the  Mediterranean 
region,  is  extensively  cultivated  in  Europe  for  its  unopened  flower 
buds,  which  preserved  in  vinegar  constitute  the  condiment  known  as 
Capers. 

ri'ome  integrifolia,  a  native  of  the  Western  Mississippi  Valley,  and 


PARIETALE8. 


553 


0.  pungens,  of  South  America,  are  fine  flowi-ring  plants  cultivated  in 
gardens. 

Order  Cruciferee. — The  Cr  ucifer  Family.  Herbs  and  a  few  low  shrubs 
with  actinomorphic  flowers,  tetradynamous  stamens, and  seeds  without 
endosperm  (Figs.  528-41).  This  large  order  includes  172  genera  and 
about  1200  species,  which  are  distributed  throughout  the  temperate  re- 
gions of  the  world,  but  are  most  abundant  in  Southern  Europe  and 
Asia  Minor.  The  prevailing  principle  in  the  order  is  pungent  and  stim- 
ulant. 

The  order  is  divided  by  Bentham  and  Hooker  into  ten  tribes,  distin- 
guished by  the  shape  of  the  fruit  and  the  disposition  of  the  cotyledons 
in  the  seed,  whether  incumbent  or  accumbent  (Figs.  536  to  541). 

The  order  furnishes  a  few  food  plants  of  some  importance. 

Bra  sica  oleracea,  a  wild  plant  of  the  Atlantic  coast  of  Europe,  is 


FIGS.  531-5. — ILLUSTRATIONS  OF  CRUCIFER.E  (SHEPHERD'S  PURSE). 


FIG.  532. 


FIG.  533. 


Fig.  531.— Vertical  section  of  flower.    Magnified. 

Fig.  532.— Pistil  and  stamens.    Magnified. 

Fig.  533.— Ripe  capsule  spli  ting  open.    Magnified. 

Fig.  534.— Seeds  on  placentie,  the  capsule-valves  removed.    Magnified. 

Fig.  53d.— Cross-section  of  capsule.    Magnified. 

probably  the  original  form  from  which  have  been  derived  by  long  cul- 
tivation the  following  races,  which  are  now  almost,  if  not  quite,  entitled 
to  be  regarded  as  species,  differing  as  they  do  fully  as  much  from  one 
another  as  many  wild  species  : 

Race  I.  Cauliflower,  in  which  the  thickened  and  consolidated  flower 
peduncles  constitute  the  edible  portion  of  the  plant. 

Race  II.  Pore  Cole  or  Kale,  in  which  the  expanded  but  tender  leaves 
of  the  tall  stem  are  the  edible  parts. 

Race  III.  Brussels  Sprouts,  resembling  the  last,  but  with  thick  edi- 
ble buds  in  the  axils  of  the  leaves. 

Race  IV.  Cabbage,  in  which  the  leaves  do  not  expand,  but  form  a  sin- 
gle  large  thick  edible  bud  or  "  head." 


554  BOTANY. 

Race  V.  Kohl-Rabi,  in  which  the  short  and  few-leaved  stem  becomes 
thick,  bulbous,  and  edible. 

B.  campefttris,  of  the  same  regions  as  the  preceding,  has  given  rise  to 
the  various  kinds  of  Turnips.  Colza  and  Rape  ali-o  are  probably  vari- 
eties ;  the  latter  are  extensively  cultivated  in  Europe  for  their  oily 
seeds,  from  which  useful  oils  are  obtained  by  pressure. 

Raphanus  sativus,  the  Radish,  is  a  native  of  China. 

Nasturtium  Armoracia,  the  Horseradish  of  Europe,  has  long  been 
cultivated  for  its  pungent  roots,  which  are  used  as  a  condiment.  Ac- 
cording to  Dr.  Gray,  the  plant,  for  some  unknown  reason,  does  not  pro- 
duce seeds  in  this  country. 

JV.  officinale,  Water  Cress  of  Europe,  and  now  run  wild  in  many  parts 

Fies.  536-41.— SEEDS  OF  CKUCIFEIUG. 


Fie.  537. 


FIG.  541. 
Fie.  539. 

Fig.  536.- Seed  of  Erysimum.    Magnified. 
Fig.  537.— Longitudinal  section  of  seed.    Magnified. 

Fig.  538.— Cross-section  of  seed,  showing  incumbent  cotyledons.    Magnified. 
Fig.  539.  -Longitudinal  section  of  seed  of  Arabia.    Magnified. 
Fig.  540. — Cross-section  of  eeed  of  Arabi*,  accumbent  cotyledons.     Magnified. 
Fig.  541.— Cross-section  of  seed  of  Barbarea,  imperfectly  accumbeut  cotyledons. 
Magnified. 

of  the  United  States,  and  many  other  rapidly  growing  foreign  and  na- 
tive species,  are  used  as  salads. 

Brasslea  alba,  White  Mustard,  and  B.  nigra,  Black  Mustard,  both 
natives  of  Europe,  are  grown  for  their  seeds,  which  when  ground  con- 
stitute the  common  condiment  Mustard.  It  is  also  of  considerable 
value  in  medicine. 

Isatis  tinctm ia,  a  tall-growing  European  biennial,  was  formerly  ex- 
tensively grown  for  the  blue  dye  obtained  from  it. 

The  most  important  ornamental  plants  of  the  order  are  the  Wall- 
flower (Cheiranthus),  Gilly  Flower  or  Brompton  Stock  (Matthiola}, 
Rocket  (Hesperid),  Candytuft  (Iberis),  Honesty  (Tsunaria),  Sweet  Alys- 
Bum  (Alyasum),  etc.,  etc. 

Several  of  the  species  are  troublesome  weeds—  eg.,  Shepherd's  Purse 
(Gapselld),  which  has  come  to  this  country  from  the  Old  World  ;  Pepper- 
grass  (Lepidium),  native  and  introduced  ;  False  Flax  ((Jamelirui)  from 
Europe ;  Charlock  and  Mustard  (Brassicd)  from  Europe. 


PARIETALES. 


555 


The  curious  plant  called  the  Rose  of  Jericho  (Anastatiea  hierochun- 
tica),  often  sold  us  a  curiosity,  is  a  small  annual,  native  of  Arabia, 
Egypt,  and  Syria.  The  mature  plant  after  ripening  its  seeds  contracts 
into  a  rounded  mass,  and  is  uprooted  and  blown  about  by  the  winds. 
When,  however,  the  dry  and  dead  plant  is  moistened,  it  expands,  clos- 


Fias.  542-5.  -ILLUSTRATIONS  OP  PAPAVEK  RHOSAB. 


Fig.  542.  -Vertical  section  of  flower.    Magnified. 
Fig.  543.— Pistil  and  stamen.    Magnified. 


FIG.  545. 


Fig.  544.— Flower  diagram. 
Fig.  545.— Ripe  fruit. 


inj?  again  when  dry.  On  this  account  it  is  also  called  the  Resurrection 
Plant. 

Order  Fumariacese. — Herbs  with  watery  juice,  alternate,  usually 
divided  leaves  ;  flowers  zygomorphic  ;  stamens  definite,  four,  five  or 
six  and  diadelphous.  Species  about  100,  natives  of  warmer  portions  of 
the  North  Temperate  Zone  and  of  South  Africa.  They  possess  an  acrid 
and  astringent  principle. 

Bentham  and  Hooker,  in  the  "  Genera  Plantarum,"  unite  this  order 


556  BOTANY. 

with  the  next,  but  this  arrangement  has  not  generally  been  adopted  by 
botanists. 

Dicentra  speetabilis,  the  Bleeding  Heart,  a  showy  Chinese  species,  is 
in  common  cultivation  for  its  heart-shaped  pink-red  flowers.  Our 
native  species,  D.  Cattadensis  and  D.  Cucullaria,  are  pretty,  and  are 
sometimes  cultivated. 

Climbing  Fumitory  (Adlumia,  rirrhosa)  is  a  delicate  native  climber, 
also  cultivated  in  gardens. 

Order  Papaveraceee.— The  Poppy  Family.  Herbs  and  a  few  low 
shrubs,  with  a  milky  or  colored  juice,  alternate  leaves,  and  actino- 
morphic  flowers ;  stamens  indefinite,  seeds  with  endosperm  (Figs.  542- 
5).  The  order  as  here  constituted  includes  about  sixty  species,  natives, 
for  the  most  part,  of  the  North  Temperate  Zone.  They  contain  a  nar- 
cotic principle. 

The  most  important  plant  of  the  order  is  the  Opium  Poppy  (Papaver 
3omniferum),  a  native  of  many  parts  of  the  Old  World,  and  now  culti- 
vated in  Southern  Europe  and  India.  Opium  is  obtained  from  it  by 
scarifying  the  full-grown  but  btill  green  capsules  ;  the  juice  which  ex- 
udes soon  hardens  and  is  then  collected,  constituting  in  this  state  the 
crude  Opium  of  commerce. 

Opium  contains  from  six  to  twelve  per  cent  of  an  alkaloid  substance, 
Morphia  (C,7  H,»  N  O3+HS  O),  to  which  its  narcotic  properties  are 
mainly  due. 

Other  species  of  Papacer,  several  of  which  are  in  common  cultiva- 
tion iu  flower-gardens,  contain  Opium,  but  it  is  not  considered  to  be  as 
valuable  as  that  from  the  Opium  Poppy. 

Sanguinaria  Canadensia,  the  Blood-root,  a  pretty  native  pl.mt  of  the 
Eastern  United  States,  contains  in  its  red  juice  narcotic  properties  sim- 
ilar to  those  of  Opium. 

Among  the  ornamental  plants  besides  Poppies  and  Blood-root,  are 
Bocconia,  a  tall-growing  Chinese  perennial,  Argemone,  from  Mexico, 
and  Eachscholtzia,  from  California. 

Order  Sarraceniaceae. — Perennial  marsh  herbs,  with  radical  tubular 
leaves,  solitary  actinomorphic  flowers  ;  stamens  indefinite  ;  seeds  with 
endosperm.  Species  ten,  nine  of  which  are  natives  of  the  United 
States.  (Figs.  546-7.) 

Sarracenui  p'tipurea,  the  common  Pitcher  Plant  of  the  Northern 
and  Eastern  United  States,  inhabits  peat  bogs  and  "  cranberry  marshes." 
Its  open,  pitcher-like  leaves  contain  water,  in  which  many  decaying  in- 
sects may  always  be  found.  The  structure  of  the  interior  surface  of 
the  pitcher  is  such  as  to  make  it  exceedingly  difficult  for  insects,  when 
once  in  it,  to  escape,  being  lined  for  some  ways  down  with  myriads  of 
short  and  sharp  stiff  bristles  which  point  downwards.  Without  doubt 
these  plants  are  nourished  by  the  decaying  insects  in  their  leaves,  and 
to  this  extent  they  are  to  be  regarded  as  saprophytes.  In  some  Southern 
species,  as,  for  example,  8.  variolari»  aud  8.  psittacina,  the  pitcher  is 


RANALES. 


557 


covered  by  a  hood  much^  as  in  Nepenthes  (page  483),  and  in  these  water 
is  also  found  (undoubtedly  a  secretion  in  these  cases)  in  which  are  many 
decaying  insects.  Moreover,  in  these  and  some  other  species  drops  of  a 
sweetish  honey-like  substance  are  secreted  on  the  leaves,  which  appar- 
ently serve  to  lure  insects  to  the  margin  of  the  pitcher. 

The  California  Pitcher  Plant  (D.irlingtonia  Ca  ifondea)  of  the  north- 
ern part  of  California,  has  long  tubular  leaves  which  are  arched  over  at 


Fie.  647. 

the  top,  so  that  the  ori- 
fice opens  downward  ; 
from  the  orifice  there 
hangs  down  a  forked 
blade,  which  is  more  or 
less  covered  with  a 
sweet  secretion,  and 
within  the  tube  there  is 
always  found  water 
more  or  less  filled  with 
insects.  The  arrange- 
ment here  is  evidently 
one  well  fitted  to  cap- 
ture insects,  which, 
after  maceration,  are 
absorbed  for  the 

jj  546.—  Flower  and  leaves  of  So.rracenia  ]»/rpiirea.  nmir;siinlpnt      of      tlin 
tural  size.— From  Le  Maout  and  Decaisr.e. 
Fig.  547.— Pistil  cut  vertically.— From  Le  Maout  and  plant. 

The  third  genus, 
Heliamphora,  contains  a  single  species,  native  of  Venezuela. 

604.— Cohort  XXXVI.  Banales. — Flowers  mostly  actino- 
morphic ;  stamens  rarely  definite ;  carpels  free,  very  rarely 
connate  ;  seeds  with  copious  endosperm. 

Order  Nymphaeacese.—  The  Water  Lily  Family.  Aquatic  herbs, 
with  usually  floating  peltate  leaves ;  flowers  solitary,  monoclinous  ; 
petals  and  stamens  generally  numerous  ;  carpels  mostly  united,  rarely 
free.  Species  thirty -five,  widely  distributed. 


558 


BOTANY. 


Nelumbium,  luteum,  the  Yellow  Water  Lilyy  or  Water  Chinquepin, 
is  common  in  the  ponds  and  rivers  of  the  Mississippi  Valley  and  the 
Southern  States.  Its  nut-like  fruits,  which  are  imbedded  in  the  large 
top-shaped  receptacle,  are  edible.  (Figs.  548-9.) 


Fig.  548.— Leaf,  flower,  and  fruiting  receptacle  of  Ndumbium  luteum.  %  natural 
size.— From  Le  Maout  aud  Decaisne. 

N.  speciosum,  the  only  other  species  of  the  genus,  occurs  in  Southern 
and  Southeastern  Asia. 

Nymphaa  odorata  and  N.  tvberosa  are  the  well-known  White  Water 
Lilies  of  the  Eastern  United  States.  JV.  ccerulea 
and  N.  Lotus  are  common  on  the  Nile. 

Victoria  regia,  the  Victoria  Lily  of  the  Ama- 
zon Valley  in  South  America,  is  remarkable  for 
the  size  of  its  leaves  and  flowers  ;  the  former  are 
peltate,  perfectly  circular,  and  two  metres  or  more 
in  diameter,  and  the  slender  petioles  are  often 
three  metres  long  ;  the  flowers  resemble  those  of 
our  White  Water  Lilies,  and  are  twenty-five  to 
thirty  centimetres  in  diameter  ;  upon  first  opening 
they  are  pure  white,  but  upon  opening  a  second 
time  they  are  of  a  pink  color. 

Order  Berberidaceee.—  The  Barberry  Family. 
Herbs  and  shrubs  with  alternate  or  radical  leaves; 
flowers  monoclinous  or  diclinous  ;  petals  and  stu- 
ng. 549.— Section  of   mcns   few  ;   carpels  one  to   three,   rarely   more, 
udcvpdf   receptade   distinct.   Species  about  100,  mostly  natives  of  cool 

climates. 

Berberis  vulyaris,  the  Barberry  of  Europe  (Figs.  550-3),  is  cultivated 
as  an  ornamental  shrub,  as  well  as  for  its  edible  acid  berries.  The 
flowers  are  interesting  on  account  of  their  sensitive  stamens,  which 


RANALE8. 


559 


move  quickly  toward  the  pistil  when  touched  at  their  bases  by  au  in- 
sect searching  for  the  honey  secreted  by  glands  upon  the  petals  (Figs. 
551-52). 

B.  (Jan'iderms,  of  the  Southern  States,  is  much  like  the  foreign  spe- 
cies. 


.Fios.  550-3. — ILLUSTRATIONS  OP  BERBERIS  VULGARIS. 


PIG.  550. 


FIG.  551. 


FIG.  552. 


Fig.  550.— Flower  diagram. 

Fig.  551.— Pistil,  with  a  petal  and  stamen.    Magnified. 

Fig.  552.— Upper  side  of  a  petal,  showing  its  two  glands.    Magnified. 

Fig.  553.— Vertical  section  of  ovary.    Magnified. 

Several  evergreen  species  from  the  Rocky  Mountains  and  Oregon, 
and  one  from  Japan,  are  cultivated  under  the  name  of  Mahonia. 

Podophyllum  peltatum,  the  May  Apple  of  the  Eas'.ern  United  States, 
produces  an  edible,  plum-shaped  fruit.  Its  poisonous  rootstocks  are 

FIGS.  554-8.— ILLUSTRATIONS  OP  MENISPERMUM  CANADENSB. 


FIG.  554. 


FIG.  557.       FIG.  558. 


Fig.  554.— Diagrnm  of  male  flower.  Fig.  555.— Fruit.    Magnified. 

Fig.  556.-Section  of  fruit.     Magnified.  Fig.  557.— Seed.    Magnified 

Fig.  558.— Section  of  seed.    Magnified. 

used  somewhat  in  medicine.     A  second  species  occurs   in  the   Him- 
alayas. 

Caulophyllum  thalictr tides,  of  the  Eastern  United  States  and  also  of 
Japan,  is  interesting  on  account  of  its  young  ovaries  bursting  open  and 
allowing  the  ovules  to  develop  into  naked  drupe-like  seeds. 


560 


BOTANY. 


Order  Menispermacese. — Woody  twining  plants,  with  alternate 
leaves  ;  flowers  diclinous  ;  petals  usually  six,  with  a  stamen  before 
(opposite  to)  each  one;  carpels  usually  three,  distinct  and  one-seeded. 
Species  eighty  to  one  hundred,  principally  tropical.  They  generally 
contain  a  bitter  principle,  which  in  some  is  tonic,  in  others  narcotic,  or 
even  poisonous. 

Menispermum  Canadense,  the  Moonseed  of  the  Eastern  United 
States,  is  a  beautiful  climber  deserving  cultivation  in  ornamental  gar- 
dens. Its  only  congener  is  a  native  of  Eastern  Asia.  (Figs.  554-8.) 


Fiss.  559-64.—  ILLUSTRATIONS  or  ASIMINA  T 


Fie.  561. 


Fio.  564. 


Fig.  559  —Section  of  flower.    Magnified. 

Fig.  560.— Flower  diagram.    Ma-rnitted.          Fig.  561.— Young  carpel.    Magnified, 


Fig.  562.—  Section  of  young  carpel.    Magnified. 


Fig.  563.— Seed.    Natural  size. 


Fig.  564.— Section  of  seed. 


Two  other  genera,  Calycocarpum  and  Cocculus,  are  represented  in 
the  United  States. 

Many  of  the  Old  World  species  are  more  or  less  in  repute  as  furnish- 
in";  medicines,  but  none  are  of  sufficient  importance  to  be  particularly 
noticed. 

Order  Anonaceee.—  Trees  and  shrubs  with  alternate  leaves  ;  flowers 
trimerous ;  stamens  indefinite,  on  a  thickened  receptacle  ;  carpels  gen- 
erally indefinite.  Species  400,  mostly  tropical.  The  bark  generally 
contains  an  aromatic  and  stimulating,  sometimes  acrid  principle. 


RANALES. 


561 


trttoba,  the  Papaw  of  the  Southern  United  States,  and  ex- 
tending to  the  Great  Lakes,  is  a  small  tree  producing  edible  pulpy 
fruits  six  to  ten  centimetres  long.  Several  other  smaller  species  of  the 
same  genus  are  common  in  the  South.  (Figs.  559-564.) 

Anona  reticulata,  the  Custard  Apple,  A.  Chenmalin,  the  Cherimoya, 
A.  squamona,  Sweet  Sop,  and  A.  muricatn,  Sour  Sop,  all  cultivated  in 
the  West  Indies  and  tropical  America,  produce  edible  fruits  ;  the  first  is 
regarded  by  some  people  as  one  of  tlie  finest  fruits  in  the  whole  world. 

Xylopia  aromatica  is  a  tree  of  western  tropical  Africa,  whose  dry 
carpels  are  aromatic,  and  used  as  pepper  under  the  name  of  Guinea 
Pepper.  The  ancients  used  this  pepper  ("  Piper  JSthiopicum  ")  long 
before  the  introduction  of  Black  Pepper. 

Fi08.  565-7.— ILLUSTRATIONS  OP  MAGNOLIA  PURPUKEA. 


FIG.  566 


Fig.  565.— Flower  cut  vertically. 

Fig.  567.-8ection  of  seed.    Magnified. 


FIG.  565. 


Fig.  566.— Flower  diagram. 


Duguetia,  quitarensis,  a  small  tree  of  Guiana,  supplies  a  tough  elastic 
wood  known  as  Lancewood. 

Order  Magnoliacese.— The  Magnolia  Family.  Trees  and  shrubs 
with  alternate  simple  leaves  ;  flowers  mostly  monoclinous  ;  petals  and 
stamens  indefinite  ;  carpels  usually  indefinite.  Species  seventy,  mostly 
of  the  tropical  and  sub-tropical  parts  of  Asia  and  America.  (Figs. 
566-7.) 

The  genus  Magnolia  contains  many  beautiful  trees,  seven  of  which 
are  natives  of  the  Southern  United  States.  Of  these  M.  noundimta,  the 
Cucumber  Tree,  extends  north  to  the  Great  Lakes,  and  sometimes  at- 


562  BOTANY. 

tains  a  height  of  forty  to  fifty  metres.  Its  light,  whitish  wood  is  valu- 
able, and  is  much  used  for  many  purposes. 

M.  grandiflo/a  is  much  like  the  preceding,  but  has  larger  flowers 
and  evergreen  leaves,  the  former  being  from  fifteen  to  twenty -five 
centimetres  in  diameter.  It  grows  only  iu  the  Southern  States,  where 
its  timber  is  somewhat  used. 

M.  Umbrella,  and  M.  macrophyl'.a  are  named  Umbrella  Trees  on  ac- 
count of  the  way  in  which  their  large  leaves  spread  from  the  ends  of 
the  branches.  The  leaves  of  the  last-named  species  are  from  fifty  to 
eighty  centimetres  (20  to  30  in.)  long,  and  the  flowers  are  from  thirty 
to  thirty-five  centimetres  (12  to  14  in.)  in  diameter. 

M.  glauca,  the  Sweet  Bay,  is  a  shrubby  species  extending  from  Louis- 
iana to  Massachusetts,  in  the  north  near  the  coast  only. 

The  foregoing  and  most,  if  not  all,  the  remaining  species  are  quite 
ornamental,  and  are  planted  wherever  they  will  endure  the  winters. 

Liriodendron  Tulipifera,  the  Tulip  Tree  or  Yellow  Poplar  of  the 
Eastern  United  States,  is  one  of  our  largest  and  most  valuable  timber 
trees.  Its  light,  whitish  or  yellowish  wood  is  much  used  in  cabinet- 
making,  coach-building,  and  for  many  other  purposes. 

Magnolia  conspicua  is  the  Yulan  Tree  of  China.  Other  species  of 
this  genus  occur  in  Japan,  China,  and  the  Himalaya  region. 

Order  Calycanthacese. — Shrubs  with  opposite  leaves  ;  seeds  with- 
out endosperm.  Three  species  occur  in  the  Southern  United  States, 
one  in  California,  and  one  in  Japan.  This  order,  the  structure  of 
which  cannot  be  discussed  here,  is  evidently  out  of  place  in  this  Co- 
hort. 

Order  Dilleniaceae. — Shrubs,  rarely  trees,  with  alternate  leaves  ; 
sepals  five,  petals  five  ;  stamens  indefinite  ;  ovaries  usually  distinct,  one- 
celled.  Species  180,  mostly  tropical. 

Two  Californian  species  of  the  genus  Crossosoma,  doubtfully  referred 
to  this  order,  are  our  only  representatives. 

Some  of  the  Indian  species  of  Dillenia  and  Wormia  yield  hard  and 
valuable  timber. 

Order  Ranunculacese. — Herbs,  rarely  shrubs,  with  mostly  alternate 
or  radical  leaves;  sepals  usually  five  or  fewer,  deciduous,  often  petal- 
oid  ;  petals  in  one  whorl,  often  wanting  ;  carpels  usually  distinct. 
(Figs.  568-73.)  Species  about  500,  most  abundant  in  temperate  and  cold 
regions.  The  herbage  usually  possesses  a  considerable  acridity. 

Formerly  many  of  the  species  were  reputed  to  be  of  medicinal  value, 
but  at  the  present  day  they  are  but  little  used  except  by  quacks.  Sev- 
eral species,  however,  still  retain  their  places  in  the  pharmacopoeias  ; 
among  these  are  : 

Aconitum  Napettus,  Monkshood  or  Aconite,  a  native  of  Europe, 
whose  roots  furnish  the  drug  Aconite, 


RANALES. 


563 


A.  ferox,  of  upper  India,  supplies  the  people  of  that  region  with  a 
virulent  poison,  with  which  they  poison  their  arrows. 
Helleborus  niger,  Black  Hellebore,  H.  fwtidm,  Stinking  Hellebore, 

FIGS.  568-73.— ILLUSTBATIONS  OF  RANUNCULACB^E  (Caltfta  palmtris). 


Fig.  568. — Flowering  ptein. 
Fig.  570.— Flower  diagram. 
Fig.  572. -Seed.  Magnified. 


Fig.  569.— Vertical  section  of  flower. 
Fig.  571.— Young  carpel.  Magnified. 
Fig.  573.— Section  of  seed.  Magnified. 


and  H.  viridis,  Green  Hellebore,  all  natives  of  Europe,  furnish  drastic 
and  poisonous  drugs. 

Among  the  ornamental  plants  of  the  order  may  be  mentioned  the 
following  : 

Anemone,  of  several  species,  including  our  native  Hepaticas,  now 
placed  in  this  genus. 


564  nor  A 


Adonis,  the  Pheasant's  Eye,  of  Europe. 

AquUegia,  the  Columbine,  including  our  common  Eastern  species  (A. 
Canadeiisis)  and  the  Rocky  Mountain  Long  Spurred  Columbine  (A. 
c&rulea),  as  well  as  the  common  one  of  Europe  (A.  vulgaris). 

Clematis,  the  Virgin's  Bower,  of  many  species,  native  and  foreign,  all 
pretty. 

Delphinium,  the  Larkspur,  of  many  species,  mostly  foreign. 

Nigella,  Love  in  a  Mist,  from  the  Old  World. 

Pceoi.ia,  the  Peony,  of  several  species,  from  Europe,  Siberia,  and 
China. 

Ranunculus,  Buttercup,  of  several  European  species. 

Trollius,  Globe  Flower,  from  Europe  and  Siberia. 

Very  few  species  afford  nutritious  products  useful  for  food  ;  the 
tuberous  roots  of  a  species  of  Ranunculus  are  gathered  and  eaten  in 
some  parts  of  Central  Europe,  and  a  few  fleshy  species  (a»,  for  example, 
Caltha  palustris,  Ranunculus  sceleratus,  etc.)  are  used  to  a  limited  ex- 
tent as  pot  herbs. 

Fossil  Dicotyledons.—  No  Dicotyledons  are  known  in  the  periods 
earlier  than  the  Cretaceous.  In  this,  however,  many  modern  orders 
are  represented.  In  the  Cretaceous  of  the  Western  Territories  of  the 
United  States  Lesquereux  describes*  one  hundred  species  of  Dicotyle- 
dons. Of  these  sixty  belong  to  the  Apetalae,  five  to  the  Gamopetalae, 
and  thirty  -five  to  the  Choripeialae  (Polypetalae).  The  Apetalae  include 
five  species  of  Populus,  six  of  Sali.r,  eight  of  Quercus,  six  of  Platanus, 
seven  of  Sassafras,  etc.  Among  the  remarkable  fossils  are  a  species  of 
Ficus  from  Minnesota,  two  species  of  Cinnamomum  from  Kansas,  and 
two  of  Laurus  from  Nebraska.  The  five  species  of  Gamopetalae  repre- 
sent the  Ericaceae  (*  sin<»le  species  of  Andromeda),  Ebenaceae  (two  spe- 
cies of  Diospyros  from  Kansas  and  Nebraska),  and  Sapotaceae  (two  spe- 
cies, one  a  Bwnnlia  from  Nebraska  and  Minnesota).  Among  the  spe- 
cies of  Choripetalae  are  five  of  Magnolia,  two  of  Liriodendron,  one  of 
Hedera,  one  of  Prunus,  one  of  Pirns,  etc.,  from  Kansas,  Nebraska,  and 
Dakota, 

In  the  Tertiary  most  of  the  more  important  orders  of  Dicotyledons 
are  represented.  Here,  as  in  the  Cretaceous,  there  is  still  a  predomi- 
nance of  Apetalous  species  ;  thus  in  the  Tertiary  Flora  of  the  Western 
Territories!  there  have  been  determined  of  the  Apetalae  one  hundred 
and  twelve  species,  Gamopetalae,  nineteen,  and  Choripetalae,  seventy- 
nine.  The  Apetalae  are  principally  represented  by  the  Myricaceae 
(twelve  species  of  Myrica),  Betulaceae,  Cupuliferae  (a  Carpinus,  a  Cory- 
lus,  a  Ftigus,  a  Caxtanea,  and  eighteen  species  of  Quercus),  Juglandaceae 

*  "  Contributions  to  the  Fossil  Flora  of  the  Western  Territories. 
Part  I.,  The  Cretaceous  Flora,"  by  Leo  Lesquereux.  Washington, 
1874. 

f  LK>  Lesquereux,  op.  cit.     Part  II.,  "The  Tertiary  Flora,"  1878 


FOSSIL  DICOTYLEDONS.  565 

(a  Carya,  a  Pterocarya,  and  seven  species  of  Juglans),  Salicaceae  (four 
species  of  Stdix  and  twelve  of  Populus),  Platanaceae  (five  species  of 
Ptatanus},  Moracese  (twenty-three  species  of  Ficus),  Lauraceae  (six  spe- 
cies of  Laurus,  one  of  Tetrantkera,  an  I  four  of  Cinnarnmnum). 

The  Gamopetalae  are  represented  b>  Caprifoliacete  (nine  species  of 
Viburnum),  Oleaceae  (four  species  of  Fraxinus),  EbenaceaB  (four  species 
ot  Diospyros),  and  Ericaceae  (an  Andromeda  and  a  Vaccinium). 

The  principal  orders  of  the  Choripetalae  are  Ampelideae  (one  species 
of  Ampdopsis,  two  of  Vitis,  and  four  of  Cissus),  Anacardiaceae  (five 
species  of  Rhus),  Cornnceae  (four  species  of  Cornus),  Khamnaceae  (ten 
species  of  Rhamnus,  five  of  Zizyphus,  three  of  Paliurus,  and  one  of 
Beichemia),  Ilicineae  (four  species  of  Hex),  Sapindaceae  (six  species  of 
Sapindus),  Myrtaceae  (two  doubtful  species  of  Eucalyptus),  Rosaceae 
(a  single  species  of  Cratcegus),  Leguminosae  (a  Podogonium,  a  Cas»ia,  an 
Acacia,  a  Mimosites,  and  two  Leguminositefi),  and  Magnoliaceae  (four 
species  of 


CHAPTER    XXI. 
CONCLUDING  OBSERVATIONS. 

605.— The  Number  of  Species  of  Plants. — It  is  impossible 
at  the  present  time  to  give  with  even  approximate  accuracy 
the  number  of  existing  species  of  plants.  In  the  first  place, 
a  great  many  species  in  all  parts  of  the  world  are  as  yet  un- 
described  ;  even  in  England,  where  the  study  of  this  branch 
of  Botany  has  been  most  energetically  pursued,  many  new 
species  are  discovered  every  year.  In  the  central  and  western 
countries  of  the  continent  of  Europe,  as  in  England,  while 
comparatively  few  flowering  plants  have  escaped  detection, 
there  yet  remain  undescribed  hundreds  of  species  of  the 
lower  groups,  and  in  the  regions  eastward  there  are  doubtless 
many  phanerogams  as  well  as  cryptogams  which  have  not  yet 
been  enumerated.  A  complete  "  Flora  of  Europe "  will 
probably  be  an  impossibility  for  very  many  years.  In  Asia 
our  knowledge  of  the  plants  is  still  more  fragmentary. 
Japan  and  India,  with  parts,  of  Asia  Minor,  are  the  best 
known  botanically,  but  even  in  these  regions  our  knowledge 
is  almost  entirely  confined  to  the  phanerogams  and  higher 
cryptogams.  In  Australia  and  the  islands  to  the  northward 
and  in  Africa,  there  are  enormous  tracts  which  have  not  yet 
been  explored.  In  the  New  World,  from  Mexico  southward, 
the  descriptions  and  enumerations  of  the  native  plants  are 
scattered  through  many  works,  not  one  of  which  approxi- 
mates completeness  even  for  comparatively  small  regions.  In 
North  America,  the  "Flora  of  North  America," begun  forty 
years  ago,  is  yet  unfinished,  even  for  the  flowering  plants.* 

*  "  A  Flora  of  North  America,"  l>y  John  Torrey  and  Asa  Gray.  Vol. 
I.,  1838-40.  Vol.  II.  (in  part),  1848."  Resumed  under  the  title  of  "A 
Synoptical  Flora  of  North  America,"  by  Asa  Gray,  1878. 


AFFINITIES  OF  THE  GROUPS.  567 

In  the  second  place,  many  of  the  so-called  species  in  de- 
scriptive works  are  but  varieties,  while  in  other  cases  the 
same  forms  have  been  described  under  different  names.  This 
is  true  in  all  the  groups  of  plants,  and  scarcely  a  monograph 
now  appears  in  which  there  are  not  cases  of  the  reduction  of 
a  supposed  species  to  a  synonym  or  variety. 

606. — With  these  considerations  in  mind,  we  may  examine 
the  catalogues  and  make  some  general  estimates.  Steudel  in 
1824  catalogued  in  "  Nomenclator  Botanicus"  59,684  phan- 
erogams and  10,965  cryptogams,  making  a  total  of  70,649. 
In  the  second  edition,  published  in  1841,  the  number  of 
phanerogams  was  increased  to  about  78,000.  Lindley,  in 
1845,  estimated  the  number  of  dicotyledons  to  be  66,488,  the 
monocotyledons  13,952,  and  the  cryptogams  12,480,  making 
a  total  of  92,820.  De  Candolle's  "  Prodromus,"  begun  in 
1824  and  continued  to  1873,  contains,  according  to  Alph.  De 
Candolle's  historical  note  in  Vol.  XVII.  of  that  work,  de- 
scriptions of  58,446  dicotyledons  and  429  gymnosperms. 

Duchartre  estimates  the  known  species  of  phanerogams  at 
about  100,000,  and  of  cryptogams  at  about  25,000,  and  ven- 
tures to  place  the  whole  number  of  species  in  the  world  at 
from  150,000  to  200,000.  Dr.  Gray  quotes  De  Candolle's 
estimate  of  the  known  species  of  flowering  plants,  amounting 
to  from  100,000  to  120,000,  and  says  that  "the  larger  num- 
ber may  perhaps  include  the  higher  orders  of  the  flowerless 
series,"  and  in  speaking  of  the  lower  cryptogams  says  that  at 
present  "no  close  estimate  can  be  well  formed  of  the  actual 
number  of  species."* 

607.— The  Affinities  of  the  Groups  of  Plants. — Many  at- 
tempts have  been  made  to  construct  diagrammatic  figures 
which  should  indicate  the  affinities  of  the  different  groups 
of  the  vegetable  kingdom.  While  it  is  impossible  to  do  this 
with  any  great  degree  of  accuracy,  we  may  yet  show  in  this 
way  certain  relations,  more  clearly  than  can  be  done  other- 
wise. The  subjoined  diagram  may  be  taken  to  indicate  in  a 
general  way  the  writer's  present  notion  of  the  affinities  (i.e., 

*  In  his  "  Botanical  Text-Book,"  1879,  Part  I.,  p.  346,  foot-note. 


568 


BOTANY. 


the  genetic  relations)  of  the  seven  great  divisions  of  plants, 
so  far  as  they  can  be  shown  upon  a  plane  surface  : 
Oamopetal(f. 

Chwipetake. 


Apetalfp. 
Monocotyledones.  I 


Dicoty 


GYMNOSPERM^E. 


PHANERO- 
GAMIA. 


PTERIDOPHYTA. 


BRYOPHYTA. 


CARPOSPORE^I. 

OOSPORE.E. 


ZYGOSPORE^L 


PROTOPHYTA. 

808.— The  Distribution  of  Plants  in  Time.  If  we  bring 
together  what  is  yet  known  as  to  Fossil  Botany  (Phytopalae- 
ontology),  as  has  been  done  by  Schimper,*  we  find  that  the 

*  "  Traite  de  Paleontologie  Vejjetale,"  par  W.  Ph.  Schimper.  Paris, 
1869  to  1874.  This  work  of  three  large  octavo  volumes  (aggregating 
2696  pp.)  and  a  quarto  atlas  of  110  plates  is  a  most,  valuable  one  for 
the  student  of  Pliytopi'ieontology. 


DISTRIBUTION  IN  TIME. 


SCO 


TABULAR  VIEW  OF  THK  DISTRIBUTION  IN  TIME  OF  THE  DIVISIONS 
OF  THE  VEGETABLE  KINGDOM. 


1 

Recent. 

1 
Pliocene. 

1 

Miocene. 

1 

i    Eocene. 

Creta- 
ceous. 

1 

Jurassic. 

Triassic, 

Permian. 

i 

Carbonif- 

I 

erous. 

o 

Devonian. 

b 

d 

5 

g 
£ 

1 

£ 

1 

1 

g 

h 
c 

Silurian. 

O 

^v 

£ 

^w^ 

4 

1 

ffi 

| 

« 

j 

s 

i 

0 

£ 

£ 

| 

1 

1 

• 

1 

0 

p, 

1 

I 

1 

1 

1 

s, 

a 

1 

I 

£ 

570  fiOTANY. 

several  Divisions  of  the  Vegetable  Kingdom  are  very  un- 
equally distributed  in  geologic  time.  Thus  no  traces  of 
Protophyta  have  yet  been  discovered  earlier  than  the  Terti- 
ary (Miocene),  while  the  Zygosporeae  appear  to  extend  back 
to  the  Secondary  (Jurassic),  and  the  Oosporese  and  Carpospo- 
reae  to  the  Silurian.  Bryophyta  have  not  been  detected  in 
strata  earlier  than  the  Eocene  (Tertiary),  while  Pteridophyta 
extend  back  to  the  Devonian.  Of  the  Phanerogamia  the 
Gymnosperms  originated  in  the  Devonian,  the  Monocotyle- 
dons in  the  Triassic,  and  the  Dicotyledons  in  the  Cretaceous. 
These  facts  may  be  more  clearly  shown  by  the  table  on  the 
preceding  page. 

It  must  be  borne  in  mind  that  our  knowledge  of  fossil 
plants  is  as  yet  extremely  limited,  a  comparatively  small 
portion  only  of  the  earth's  strata  having  hitherto  been  care- 
fully examined.  It  is  very  probable  that  as  we  come  to 
know  more  of  the  fossil  remains  of  plants  some  or  all  of  the 
lines  in  the  table  will  be  extended  downward.  On  the  other 
hand,  we  need  not  expect  to  find  many  remains  of  the  ex- 
ceedingly simple  organisms  which  constitute  the  Protophy- 
ta, although  they  probably  have  existed  in  abundance 
since  pre-Silurian  times.  So,  too,  few  Zygosporeae  have  a 
sufficiently  durable  plant-body  to  allow  them  to  be  preserved 
in  a  fossil  state.  The  softness  of  texture  and  easy  perisha- 
bility of  the  tissues  of  the  Bryophyta,  especially  in  the  lower 
orders,  probably  accounts  for  the  few  fossil  remains  hitherto 
discovered.  Doubtless  we  must  in  the  same  way  account  for 
the  fact  that  most  of  the  species  of  fossil  Phanerogams  are 
trees  and  shrubs;  the  softer  tissues  of  the  herbaceous  spe- 
cies have  yielded  but  few  fossils  as  compared  with  the  harder 
arid  denser  ones  of  the  ligneous  species. 


INDEX   TO   THE   ILLUSTRATIONS. 


ABIES  PECTINATA,  394,  397,  401 

Acer  dasvcarputn,  74 

Acer  Pseudo-Platanus,  536 

Achlya,  40,  255 

Achlya  racemosa,  256 

Acorus  calamus,  114,  115,  116 

Adiantum,  374 

Adiantum    Capillus-Veneris,    370, 

371,  372 

Adiantum  Moritzianum,  109 
JSsculus,  5)37 

^Esculua  Hippocastanum,  141 
Agaricus  campestris,  326,  327 
Ailantlius  glandulosus,  125,  448 
Alisma  Plantaoro,  467 
Allium  cepa.  423 
Alsophila,  377 

Ampelopsis  quinquefolia,  154 
Auagallis  arvensis,  507 
Anauassa  saliva,  471 
Antlioceros  laevis,  348,  350 
Arabis,  554 

Arcyria  incarnata,  210 
Aristolochia  siplio,  84 
Asclepias,  504 
Ascobolus  f urfuraceua,  288 
Asimina  triloba,  560 
Aspidium  Filix-mas.  41,  374.  075, 

376 
Asplenium,  374 

BACILLUS  ULNA,  213 
Bacterium  lineola,  213 
Bacterium  Termo,  213 
Banana,  472 
Barbarea,  554 
Beet,  60,  495 
Begonia,  30 
Berberis  vulgaris,  559 
Beta  vulgaris,  495 
Betula  alba,  12r>,  127 
Biota  orientalis,  396 


Bittersweet.  501 
Botrychium  Lunaria,  378.  879 
Bryum  argenteum,  359 
Buckwheat,  162 
Bulboclisete  intermedia,  248 

GALLITRIS  QUADRIVAI.VIS,  899 

Caltha  palustris,  563 

Camellia  Cliinensis,  548 

Canna.  473 

Capsella  Bursa-pastoris,  424,  553 

Carya  alba,  73 

Cassia  tora,  533 

Castanea  vesca,  153 

Cephalotus  follicularis.  527 

Oerastium  collinum,  550 

Ceratozamia  longifolia,  396 

C^bara  fragilis,  332,  333 

Chenopodium,  496 

Cherry,  143 

Chestut,  153 

Chondrioderme    difforme,    36,    44, 

209,  21C 

Cichorium  intybua,  23 
Citrus  Aurantium,  541 
Clavicepa  purpurea.  290  291, 
Clematis  Viticella,  439 
Cnicus  altissimus,  98 
Cocoa-nut,  463 
Coffea  Arabica,  517 
Colcbicum  autumnale,  459 
Coleochaete  pulvinata,  272 
Collema  Jacobaefolium,  300 
Collema  microphyllum,  300 
Collema  pulposum,  309 
Corallina  officinal  is,  274 
Cosmarium  Menenghinii,  44,  226 
Cucumis  Mfclo,  521 
Cucurbita,  95 
Cucurbita  Pepo,  29,  77 
Cupressus  sempervireus,  396 
Cycas  revoluta,  400 


572 


INDEX  TO   THE  ILLUSTRATIONS. 


Cypripedium  calceolus,  470 
Cystopus  candidus,  259,  262 
Cytisus  Laburnum,  84,  447 

DAHLTA  VARIABTT.IS,  27,  33 

Date.  452,  463 

Diagrams,  33,  38,  138,  139, 403,  406, 

417,  420,  445,  450,  468 
Dictatnnus  fraxinella,  131,  542 
Didymium  serpula,  78 
Dionsea  muscipula,  525 
Dorstenia,  489 
Dracaena,  444 
Dudresnaya  purpurifera,  276 

ECHINOCYSTIS    LOB  ATA,  30,  70,  71, 

73,  100,  155,  156 
Equisetuin  arvense,  36o 
Equisetum  limosum,  365 
Equisetum  paluatre,  110 
Equisetum  scirpoides,  88 
Equisetum  Telmateia,  364,  366 
Erica  cinerea,  509 
EryBimum,  554 
Erysiphe  Cichoriacearum,  281 
Erysiphe  Tuckeri,  279 
Eschscholtzia  Californica,  419 
Eucalyptus  globulus,  524 
Eupatorium,  515 
Euphorbia,  75 
Eurotium  repens,  282 

FAGOPYRUM  ESCULENTUM,  162,  496 
Fern  prothalliurn,  370 
Ficus,  489 

Fcenlculum  vulgare,  519 
Fontinalis  antipyretica,  87,  142,  359 
Fragaria  vesca,  529 
Fritillaria  imperialis,  3,  458 
Fuchsia  globosa,  104.  105 
Fucus  platyearpus,  266 
Fucus  vesiculosus,  267 
Fuligo  varians,  4,  209 
Funaria  hyjrrometrica,  48,  52,  353, 
354,  356,  358 

GlNKGO  BILOBA,  399 
(tleichenia,  377 
(ilceocapsa,  216 
(iomphidium,  8ii9 
Gordonia  Lasianthus,  547 
Urape,  79,  80 
Uraphis  elegans,  309 

HBDKKA  IIKMX,  130 


Hemlock  Spruce,  152 
Hickory-nut,  73 
Hop,  97 

Horsechestnut,  141 
Hoya  carnosa,  34 
Hyacinthus  orientalis,  101 
Hydrodictyon  utriculosum,  223 
Hypericum  calycinum,  549 

Iberis  ainara.  442,  443 
Impatiens  Balsamina,  28,  82,  543 
Indian  Corn,  2,  6,  55,  67,   113,  154 

160,  451.  452 

Iridaceae  (flower  diagram),  468 
Isoetes  lacuatris,  387,  388 
Ivy, 130 

Juglaus  regia,  481 
Juncus  effusus,  20 
Juniperus  communis,  402,  407 

Lamium,  498 
Lathyrus  odoratus,  531 
Lathyrus  Pseudaphaca,  440,  441 
Laurus  nobilis,  492 
Lavatera  trimestris,  23 
Lecanora  subfusca,  297 
Lejolisia  mediterranea,  274,  275 
Lemna  minor,  462 
Linum  usitatissitnum,  544 
Lycopodium  annotinum,  383 
Lycopodium  clavatum,  383 
Lycopodium  complanatum,  112 

Magnolia  purpurea,  561 
Mallotium  Hildenbrandii,  303 
Malva  eylvestris,  546 
Marchantia    polymorpha,    91,    92. 

344,  345,  346,  347,  349,  350 
Marsilia  salvatrix,  381 
Megalospora  affiuis,  299 
Menispermum  Canadense,  559 
Micrococcus  prodigiosus,  213 
Mimosa  pudica,  534 
Mucor,  33S 
Mucor  Mucedo,  236 
Mucor  stolonifer,  237,  238 
Musa  sapientum,  472 
Mustard,  95 
Myristica  fragrans,  493 
Myrtus  communis,  524 

Navicula  saxonica,  229 
Navicula  viridis,  228 
Nelumbium  luteuui,  558 


INDEX  TO    THE  ILLUSTRATIONS. 


573 


Nemalion  multifidum,  275 
Nepenthes  ampullaria,  483 
Nitella  flexilis,  331 
Nostoc,  37,  217 
Nuphar  adveua,  20 

Oat,  454 

Ochrolechia  pallescens,  299 

(Edogonium,  22,  247 

(E^iogonium  ciliatum,  248 

(Edogonium  gemelliparuin,  248 

Onion,  76 

Orchis  mascula,  469 

Oscillatoria,  37,  217 

Osmunda,  877 

P;ilm  (stem),  443 

Pandorina  Morum,  222 

Papaver  Rhoeas,  555 

Parmelia  aipolia,  296 

Parmelia  tiliacea,  302 

Peach  (flower),  530 

Pediastrum  granulatum,  65,  224 

Penicillium  chartarum,  285 

Peronospora,  261 

Peronospora  Alsinearutn,  48,  261 

Peronospora  calotheca,  258 

Peronospora  infestans,  258 

Pertusaria  ceuthocarpa,  299 

Pertusaria  Wuli'eni,  309 

Peziza  confluens,  286 

Peziza  convexula,  42,  287 

Peziza  omphalodes,  287 

Phaseolus  multiflorus,  43,  475 

Phoenix  dactylifera,  452 

Phragmidiuiu  bulbosum,  315 

Phragmidium  mucronatuni,  315 

Physarum  leucopus,  208 

Pilularia  globulifera,  380 

Pinus  Larico,  401 

Pinus  pinaster,  72,  124 

Pinus  Pinea,  405 

Pinus   sylvestris,  25,  26,   394,  395 

398 

Piptocephalis  Freseniana,  239 
Pirus  communis,  528 
Pirus  Cydonia,  528 
Pisum  sativum,  54 
Plagiochiiia  aspleniotdett,  349 
Polypodium,  373 
Polypodiura  vulgare,  108 
Potainojreton  pectinatus,  129 
Potato  (flower),  501 
Primula  sinensis,  97 
Prunns  Cerasus,  530 


Psoralea  bituminosa,  122,  476 
Pteris  aquilina,  24,  27,  72,  81,  83, 

107.371.372,373 
Puccinia  graminis,  311,  313 
Puccinia  Moliniae,  314 

QUINCE,  528 

Quercus  Robur,  449,  478 

RANUNCULUS  REPENS,  119 

Rhizomorpha  subcorticalis,  66 

Rhubarb,  60 

Riccia  jjlauca,  345,  346 

Rice.  455 

Ricinus  communis,  117,  118,  474 

Rosa  canina,  427 

Rosa  rubigiuosa,  429 

Rye,  96 

SACCHAROMYCES  CEREVISI.E,    39, 

214 

Salix  capraea,  486 
Salvinia  natans,  380,  381 
Sambucus  nigra,  445,  446 
Saprolegnia,  255 
Saprolegnia  androgyna,  257 
Sarracenia  purpurea,  557 
Schizwa,  377 
Scorzonera  Mspanica,  75 
Scrophularia.  499 
Sedum  purpurascens,  101 
Selaginella  caulescens,  384 
Selaginella  inaequifolia,  111.  386 
Selaginella  Martensii,  384,  385 
Sequoia  giorantea,  80 
Shepherd's  Purse,  553 
Silphium  laciniatum,  157 
Solanum,  501 

Sorisporiutu  Saponariae,  320 
Sphaeria  morbosa.  293 
Sphaarophorus  globiferus,  298,  302 
Sphseroplea  annulina,  245 
Sphserotheca  Castagnei,  280 
Sphaerotheca  pannoea,  280 
Sphagnum  acutifolium,  355 
Sphagnum  squarrosum,  355 
Spirillum  volutans,  213 
Spirochaete  plicatilis,  213 
Spirogyra  longata,  45,  46,  51,  233 
Stachys  angustifolius,  441 
Sticta  fuliginosa,  295 
Sticta  pulmonacea,  308 
Stipa  spartea,  158 
j  Sunflower,  68 


5T4 


INDEX  TO    THE   ILLUSTRATIONS. 


TARAXACUM  DENS  LEONIS,  513 
Tax  us  baccata,  895 
Tetragonolobus  531 
Theobroma  Cacao,  545 
Thistle,  98 
Tilletia  caries,  321 
Tradeacautia  Virginica,  12 
Trapa  natans.  163 
Trichomanes,  377 
Tsuga  Canadensis,  152 
Tuber  melanosporum,  285 

ULVA,  224 

Uncinula  adunca,  281 

Urtica  macrophylla,  61 

Urtica  nrens,  491 

Usnea  barbata,  302.  304,  308 

Ustilago  antherarura,  320 

Ustilago  Maydis,  320 


VACCINIUM  MYRTILLUS,  511 

Vanilla  planifolia,  471 

Vauclieria   sessilis,  47,    251,    252, 

253 

Vibrio  Rugula,  213 
Vicia  faba,  38,  69,  474 
Viola  tricolor,  20,  422,  423 
Virginia  Creeper,  154 
Vitis,  79,  80 
Vitis  vinitera,  538 
Volvox  globator,  244 

WALLFLOWER,  552 
\Velwitscliia  mirabilis,  60,  414 

YEAST  PLANT,  39,  214 

ZEA  MAIS,  113, 154,  160.  451,  452 


GENERAL    INDEX. 


Abele  Tree,  487 

Abies,  81,  151,  394,  397,  409,  411, 

412,  415 
Abietineae,  410 

Abortion  of  Floral  Organs,  431 
Abridgment  of  Life  Cycle,  314 
Abronia,  497 
Absinthe,  514 

Absorption  of  Food,  176,  184,  191 
Acacia,  533,  534,  565 
Acauthace*,  61,  499 
Acanthus  Family,  499 
Accumbent  Cotyledons,  437 
Acer,  72,  75,  535 
Acerineaj,  119,  535 
Achene,  436 
Achenial  Fruits,  436 
Achimenes,  499 
Achlamydeous,  431 
Achlya,  39,  256 
Achtianthes,  230 
Achnanthidium,  230 
Achyranthes,  496 
Acids,  62 
Acolium,  310 
Aconite,  562 
Aconitutn,  106,  562 
Acorus,  58,  114,  462 
Acrocarpae,  359,  360 
Acroscyphus,  310 
Acrostichum,  377 
Actinocyclus,  231 
Actinodiscus,  231 
Actinoniorphic,  430 
Actinoptychus,  231 
Acyclic  Flowers,  429 
Adam's  Needle,  461 
Adder  Tongues,  372 
Adiantum,  110,377 
Adluuiia,  556 
Adnate  Anthers,  433 


Adnation  of  Floral  Organs,  432 

Adonis,  53,  564 

Adventitious  buds,  143 

Adventitious  stems,  143 

.iEcidiospores,  312 

.Ecidium,  312,  316 

.JSgilops,  455 

Aerial  roots,  137 

^Isculus,  537 

^thalium,  210 

^Ethusa,  520 

Affinities  of  Plants,  567 

Agapanthus,  400 

Agaricaceas,  339 

Agarics,  241 

Agaricu?,  39,  323,  328,  329,  330 

Agave,  467 

Ageratum,  98 

Aggregate  fruits,  436 

Aggregations  of  cells,  65 

Agrimony,  149 

Agrostis,  455 

Ailanthus,  102,  541 

Air  in  the  Plant,  174 

Albuminous  seeds,  391,  437 

Albuminoids,  51) 

Alders,  488 

Alectoria,  308 

Alectryon,  535 

Aleurites,  485 

Aleurone,  57 

Alfilaria,  543 

Alga,  133 

Algse,  53,  55,  86,  135,  204,  205,  221, 

337,  340 
Algales,  337 
Alisma  467 

Alismacese.  128,  425,  466 
Alkaloids,  62,  182 
Alkanet.  502 
Allamauda,  504 


07G 


GENERAL   INDEX. 


Alligator  Pear,  494 

Allium,  458 

Allspice,  523 

Almond,  530 

Alnus,  488 

Aloe,  458 

Aloes,  459 

Alsophila,  377 

Alternate  leaves,  149 

Alternation    of    Generations,  341, 

361 

Althaea,  547 
Alyssum,  98,  554 
Amarantaceae,  496 
Amarantus,  264,  496 
Amaryllidaceae,461,  467 
Amaryllis,  468 
Amaryllis  Family,  467 
Amaurochaeteae,  210 
Ambrosia,  264,  429,  515 
Amelancbier,  527 
Amentales,  485 
Aments,  413 
American  Larch,  412 
American  White  Ash,  505 
American  White  Elm,  488 
Ammonia  Salts,  176 
Amosba  movement,  8 
Amole,  468 
Amomales,  471 
Amoreuxia,  551 
Amorphophallus,  462 
Amount  of  Evaporation,  171 
Amount  of  Water  in  Plants,  166 
Ampelideae,  537,  565 
Ampelopsis,  165,  194,  538.  565 
Amphigastria,  344,  351 
Amphipleura,  230 
Amphora,  230 
Anacardiaceae,  534,  565 
Anacardium,  535 
Anacharis,  473 
Anaesthetics,  198 
Anagallis,  434.  436,  507 
Analojry  and  Homology,  120 
Ananassa,  471 
Anastatica,  555 
Ancestry  of  Plants,  204 
Anchusa,  502 
Andrea,  358 
Andreaceae,  355,  358 
Androecium,  418,  430,  432 
Androgynia,  250 
Andromeda,  504,  565 


Andromedeae,  510 

Androspore,  249 

Anemeae,  210 

Anemone,  102,  264,  284,  429,  563 

Anemia,  377 

Anerniopsis,  483 

Anemophilous  Flowers,  421 

Angiocarpous  Lichens,  297,  298 

Angiopteris,  378 

Angiosperma?,  393,  416,  568 

Anofiosperms,  79,  85 

Angular  divergence  of  leaves,  150 

Angustura  Bark,  542 

Aniseed,  520 

Annual  layers  of  wood,  447 

Annular  Vessels,  118 

Annul  us,  328,  375 

Anona,  561 

Anonacese,  560 

Anortheis,  230 

Anthemideae,  514 

Anthemis,  514 

Anther,  394,  417,  418 

Antheridial  disc,  347 

Antheridium,  45,  243,  266, 271,  331, 

341,  3*61 

Anther  Smut,  318 
Anthesis,  199 

Anthoceros,  11,  217,  341,  348,  350 
Anthocerotese,  350,  361 
Antiaris,  490 
Antipodal  Cells,  420 
Antirrhinum,  150,  500 
Apetalae,  476,  568 
Apetalous,  431 
Aphyllon,  192 
Apical  Cell,  38,  86,  88,  153,  343, 

352,  363,  373,  378,  380,  381,  425 
Apium,  519 
Appendages,  281 

Apple,  64,  159,  171,  284,  436,  527 
Apocarpous,  433 
Apocynaceie,  77,  119,  504 
Apocynuin,  504 
Apostasiacete,  469 
Apothecium,  297 
Apricot,  62,  530 
Aqueous  Tissue,  94 
Aquilegia,  564 
Arabia,  437 

Aracese  (=Aroidese),  77 
Arachis,  532 
Arachnoidiscus,  231 
Arales,  461 


GENERAL  INDEX. 


577 


Aralia,  519 

Araliaceae,  519 

Araucaria,  409,  413, 414 

Araucarieae,  413 

Arbor  Vitas,  411 

Arbutus,  509 

Arceuthobium,  477 

Archas,  506 

Arcbegonium,  46,  341,  361,  402 

Arcbespennae,  393 

Archidium,  358 

Arctopodiuui,  385 

Arctostapbylos,  156,  509 

Arctoideae,  514 

Arcyria,  211 

Areca,  466 

Arecinese,  466 

Aretbusa,  470 

Aretliuseae,  470 

Argemone,  556 

Aril,  437 

Arisaema,  61,  462 
Aristolochia,  482 

Aristolocbiaceae,  482 

Armeria,  508 

Arnica,  514 

Aruotto,  551 

Aroidese,  119,  461 

Aroids,  461 

Arrack,  464 

Arrangement  of  Leaves,  149 

Arrangement  of  Roots,  164 

Arrowroot,  473,  484 

Artemisia,  85,  514 

Artbonia,  310 

Anboniei,  310 

Articboke,  512,  515 

Artocarpus,  489 

Arum  Family,  461 

Asafoetida,  63,  520 

Asarales,  482 

Asarum,  482 

AsclepiadHcese,  77.  119,  503 

Asclepias,  102,  420 

Ascobolus,  288,  289,  301 

Ascogonium,  300 

Ascomycetes,  214, 270, 271, 273, 278, 

305,  335,  337,  338,  340 
Ascosporeae,  339 

Ascospores,  40.  214,  278,  315,  319 
Ascus,  278,  315,  319 
Ascyrum,  549 

Asexual  Generation,  341,  361 
Ash,  436 


Asb  Tree,  505 
Asimina,  561 
Asparagus,  458 
Aspergillus,  284 
Asphodel,  460 
Aspbodelus,  460 
Aspidium,  377 
Asplenium,  377 
Assimilation,  62,  178,  185,  191 
Astepbanae,  334  . 
Aster,  516 
Asterales,  512 
Asteroideje,  516 
Asterolampra,  231 
Asterolampreae,  231 
Asteropbyllites,  368 
Astilbe,  526 
Astragalus,  532 
Aatrocaryum,  17 
Astrotricbia,  520 
Asymmetry  of  Leaves,  146 
Atalea,  464 
Atberosperma,  494 
Atmospberic  pressure,  171 
Atricbum,  352 
Atriplex,  52 
Atropa,  502 
Aucuba.  518 
Aulacodiscus,  231 
Auliscus,  231 
Aurantieae,  541 
Auricula,  506 

Australian  Pitcber  Plant,  52? 
Austrian  Pine,  412 
Autogamous  Flowers,  421 
Autumn  Crocus,  460 
Auxospores,  228 
Avena,  102,  455 
Avocado  Pear,  494 
Axile  Placenta,  433 
Azalea,  510 
Azolla,  381,  382 

Baccate  Fruits,  436 
Baccate  Seeds,  437 
Bacillariaceaa,  227 
Bacillus,  213 
Bacteria,  65,  212 
Bacteriaceae,  212 
Bacterium,  17,  213 
Bactrospora,  298 
Baeomyces,  310 
Balanopborese,  476 
Bald  Cypress,  411 


GENERAL  INDEK. 


Balloon  Vine,  537 

Balm,  498 

Balsam,  61,  94,  144,  542 

Balsam  Apple,  522 

Balsam  Fir,  412 

Balbamodendrou,  540 

Balsam  of  Peru,  5152 

Balsam  of  Tolu.  532 

Bamboo,  453,  457 

Bambusa,  457 

Banana,  146,  472 

Banana  Family,  471 

Bauds  of  Protoplasm,  16 

Baugiacese,  339 

Banksia,  491 

Banyan  Tree,  490 

Baobab,  474 

Bapbia,  532 

Barberry,  197,  316,  558 

Barberry  Cluster  Cups,  316 

Barberry  Family,  558 

Barberry  Rust,  316 

Barbula,  351,  360 

Barcelona  Nuts,  477 

Bark,  118,  124,  201,  393,  409,  447 

Barley,  59,  187,  319,  322.  323,  455 

Barosina,  542 

Bartramia,  359 

Basal  Cells,  206 

Basellaceae,  494 

Basidia,  323 

Basidiomycetes,  270,  323,  335,  337, 

338,  339,  340 
Basioiosporeae,  339 
Basidiospores,  39,  323,  328 
Bassia,  506 
Bassorin,  63 
Basswood,  545 
Bast  Cells,  17 
Bast  Fibres,  74,  76,  119 
Bast,  Soft,  116 
Bathybius,  15 
Batrachospermeaj,  277 
Bayberry,  487 
Bay  Tree,  493 
Bdellium,  465,  540 
Bean,  56,  58.  59,  199,  435,  531 
Bearberry,  509 
Bear  Grass,  461 
Bedfordia,  514 
Bedstraw,  517 
Beech,  125,  126,421,  479 
Beech  Mast,  479 
Beech  Nuts,  479 


Beet,  166,  495 

Begonia,  61,  94, 143,  146,  521 

Begoniaceae,  71,  521 

Belladonna,  '.02 

Bellis,  516 

Berberidacese,  558 

Berberis,  85,  102,  558 

Berchemia,  565 

Berry,  436 

Benholletia,  58,  523 

Beta,  103,  495 

Betel  Nut,  466 

Betel  Palm,  466 

Betel  Pepper,  484 

Betula,  102,  174,  487 

Betulacete,  487,  504 

Bhang,  488 

Biatora,  310 

Bicol lateral  Bundles.  121 

Bicyclic,  430,  432 

Biddulphia,  3:31 

Biddulphiea?,  231 

Bidens,  264,  515 

Bignouia,  81,  85,  426,  499 

Bignoniacese,  499 

Big  Trees  of  California,  411 

Bilaterality  of  Leaves,  146 

Bilocular,  433 

Biota,  409 

Biparous  Cyme,  429 

Birch,  126,  174,  421,  437,  487 

Birch  Family,  487 

Bird  Cherry,  530 

Birds  Aiding  in  Pollination,  421 

Bisexual  Flowers,  431 

Bittersweet,  539 

Bixia,  551 

Bixineae,  551 

Black  Ash,  505 

Blackberry,  426,  437,  529 

Black  Bindweed,  497 

Black  Grain.  532 

Black  Huckleberries,  511 

Black  Jack  Oak,  480 

Black  Knot,  292 

Black  Nightshade,  502 

Black  Oaks,  480 

Black  Pepper,  483,  5<>l 

Black  Rust,  316 

Bladder-nut,  535 
i  Bladderwort  Family.  499 
|  Blanching  of  Celery,  52 
i  Blanc  Man-re,  277 
I  Blazing  Star,  516 


GENERAL  INDEX. 


Bleeding  Heart,  556 

Bletia,  470 

Blood-root,  556 

Bioodwood  Tree,  523 

Bloodwort  Family,  467 

Blueberry,  511 

Blue  Beech,  477 

Blue  Gum,  524 

Blue  Huckleberries,  511 

Blue  Mould,  285 

Blue  Palmetto,  465 

Bluets,  517 

Bocconia,  556 

Bcehmeria,  491 

Boletus,  330 

Bombax,  547 

Borage  Family,  502 

Borassineae,  465 

Borassus,  465 

Bordered  Pits,  251 

Bore  Cole,  553 

Boronieae,  542 

Borraginacete,  150,  502 

Bostryx,  429 

Boswellia,  540 

Botrychiuni,  379,  380 

Botrydium,  134 

Botry-Cyme,  429 

Botryose  Inflorescence,  427,  428 

Botryose  Mouopodium,  140 

Bouncing  Bet,  550 

Boundary  Tissue,  89 

Boussingaultia,  494 

Bouvardia,  518 

Bow- wood,  490 

Box  Elder,  536 

Box  Tree,  485 

Bracts,  136,  155 

Bran-cell,  58 

Branching,  Modes  of,  139 

Branching  of  Leaves,  147 

Branches  of  Stems,  142 

Brass! ca,  98,  102,  150,  553 

Brazilian  Arrowroot,  484 

Brazilian  Artichoke,  515 

Brazil  Nut,  58,  524 

Brazil  wood,  533 

Mread-Fruit  Tree,  489 

Break- Ax  Tree,  545 

Bristles,  137 

British  Oak,  479 

Bromeliaceae,  471 

Brompton  Stock,  554 

Broom  Corn,  457 


Brosimum,  489,  490 
Broussonetia,  490 
Bruchia,  358 
Brucia,  503 
Bruniacese,  526 
Brussels  Sprouts,  553 
Bryacese,  355,  358 
Bryophyllum,  143,  526 
Bryophyta,  205,  305,  341,  568,  569, 

570 
Bryophytes,  10,  40,  59,  67,  72,  87, 

90,  124,  140,  143.  145,  265,  341. 

389 

Bryum,  352,  359,  360 
Buchu,  542 
Buckeye,  537 
Buckthorn,  539 
Buckwheat,  496 
Buckwheat  Family,  496 
Buckwheat  Tree,  539 
Bud,  139,  140,  181,  189,  199 
Bud-cell,  332 
Buellia,  310 
Buffalo  Berry,  492 
Bulb,  181,  190,  191 
Bulb-axes,  136 
Bulbochsetacese,  269 
Bulbochsete,  250 
Bulbophyllurn,  471 
Bulgaria,  289 
Bumelia,  506,  564 
Bundles,  Fibro-vascular,  106 
Bundle  Sheath,  108, 114 
Bunt,  318 

Burgundy  Pitch.  412 
Burmanniacese,  468 
Burning  Bush,  5o9 
Bursera,  540 
Burseraceae,  540 
Bush  Honeysuckle,  518 
Butcher's  Broom,  461 
Buttercup,  564 
Butternut,  482 
Butter  Trees,  506 
Button  Bush,  517 
Button  wood,  487 
Buxus,  102,  485 

Cabbage,  93.  171,  185 
Cabbage  Palmetto,  565 
Cacalia,  514 
Cachibou,  540 
Cactaceae,  94,  520 
Cacti,  503 


580 


GENERAL   INDEX. 


Cactus  Family,  520 

Caslosphaerium,  216 

Caesalpina,  533 

Csesalpinieae.  533 

Caffeine,  183 

Calabash  Tree,  499 

Calamandar  Wood,  506 

Calamarieae,  368 

Calamese,  465 

Calamites,  368 

Calamocladus,  368 

Calamostachys,  368 

Calamus,  81,  465,  466 

Calandrinia,  549 

Calcarea?,  210 

Calceolaria,  500 

Calcium,  175 

Calcium  Carbonate,  60 

Calcium  Oxalate.  59,  180 

Calendulaceae,  514 

Caliciacei,  310 

Caliciei,  310 

Calicium,  310 

California  Laurel,  494 

California  Pitcher  Plant,  557 

Calla,  61,  462 

Calla  Lily  462 

Calliope'.,,  514 

Callirhoe,  547 

Callistephus,  516 

Callithamnion,  277 

Callitris,  399,411 

Calluna,  509 

Calocasia,  462 

Calonemeae,  211 

Calophyllum,  549 

Calopogon,  470 

Caltha,  436,  564 

Calycanthaceae,  562 

Calyceracese,  516 

Calycocarpuiu,  560 

Calypso,  471 

Calyx,  418,  430 

Cambium,   17,  116,  121,  143,  164, 

201,407,  444 
C'ambiform  Cells,  111 
Camelina,  554 
Camellia,  548 
Campanales,  511 
Campanula,  11,  13,  512 
Campanulacese,  77,119,  511 
Camphor,  63,  494,  547 
Camphor  Tree,  547 
Camwood,  532 


Canada  Balsam,  412 

Canada  Thistle,  513 

Canal,  Intra-fascicular,  111 

Candle  Nut  Tree,  485 

Candytuft,  554 

Canella,  551 

Canella  Bark,  551 

Canellaceaj,  551 

Cane  Palms,  465 

Cane  Sugar,  62,  180 

Canna,  473 

Cannabis,  488 

Cannabineae,  488 

Cannacete,  425 

Cannae,  473 

Canon  Live-Oak,  479 

Canterbury  Bells,  512 

Caoutchouc,  78,  485,  490,  503,  504 
I  Capers.  552 

Capillitium,  210 

Capparidaceae,  5V3 

Capparis,  552 

Caprifoliaceze.  518,  565 

Capsella,  98,  264,  425,  554 

Capsicum,  501 

Capsulary  Fruits,  436 

Capsule,  348,  355,  43(3 

Caragaua,  532 

Caraway,  520 

Carbon,  175 

Carbonates,  176 

Carbohydrate,  178 

Carbon' Dioxide,  174,  181,  191 

Carbon  Oxide,  179 

Career u I  us,  436 

Cardinal  Flower,  512 

Cardiospermum,  537 

Carex, 150, 323 

Carica,  522 

Carludovica,  462 

Carnations,  550 

Carnivorous  Plants,  182 

Carmine,  520 

Carpel,  136.  430,  433 

Carpellary  Leaves,  400 

Car  pet -weed,  520 

Carpids,  433 

Carpinus,  477,  564 

Carpogoniuui,  271,  300,  330,  331 

Carpophore,  436 
|  Carpophyllum  (pi. -la,)  419,  433 

Carpospore,  332 

Carpospoie*.    205,  270,   335,  837, 
568,  569,  570 


GENERAL   INDEX. 


581 


Carrot,  519 

Carthamus,  512 

Carya,  73,  482,  565 

Caryophyllacete,  494,  549 

Caryophyllales.  549 

Caryopsis,  436 

Caryota,  466 

Cascarilla  Bark,  485 

Cashew  Family,  534 

Cashew  Nut,  535 

Cassava,  484 

Cassia,  197,  533,  565 

Cassia  Bark,  494 

Cassia  Buds,  494 

Castanea,  478,  564 

Castilleia,  53 

Castilloa,  490 

Castor  Bean,  59,  181 

Castor  Oil,  62 

Castor  Oil  Plant,  475,  484 

Casuarineae,  487 

Catalpa,  429,  437,  499 

Catasetuin,  470 

Catchfly,  550 

Catha,  539 

Catkin,  395,  413,  428 

Catnip,  498 

Cattleya,  471 

Caulei-pa,  134,  254 

Caulerpites,  254 

Caulicle,  404 

Cauliflower,  553 

Cauline  Bundles,  392,  442 

Cauloine,  134,  135,  243,  271 

Caulophyllum,  559 

Cayenne  Pepper,  501 

Ceanothus.  61,  103 

Cedrella,  540 

Cedrus,  409,  415 

Celastraceae,  539 

Celastrales,  537 

Celastrus,  539 

Celery,  519 

Cell  Derivatives,  67 

Cell  Families,  65 

Cell  Formation  by  Division,  36 

Cell  Formation  by  Union,  44 

Cell  Fusions,  66 

Cell  Masses,  67 

Cell  Rows,  67 

Cell  Sap,  62 

Cell  Surfaces,  67 

Cellular  Plants,  205 


Cell  Wall,  15,  21,  68,  168,  206 

Celosia,  496 

Celtis,  61,  85,  150,  488 

Cellulose,  21 

Cenangiurn,  289 

Ceutaurea,  513 

Central  Cell,  331,375 

Centrifugal  Thickening,  31 

Centripetal  Thickening,  31 

Century  Plan' ,  467 

Cephaelis,  517 

Cephalanthus,  517 

Cephalotus,  526 

Ceramieae,  277 

Ceramiaceae,  339 

Ceramium,  278 

Cerasin,  63 

Cerastium,  429,  550 

Ceratophyllese,  483 

Ceratozarnia,  410 

Cercis,  533 

Cercocarpus,  529 

Cereus,  520 

Cereal  Grains,  181 

Ceropegia,  503 

Ceroxylon,  93,  466 

Cestrum,  502 

Cetraria,  308 

Chaetocereae.  231 

Chaetoceros,  231 

Chaetocladium,  241 

Chailletiacese,  540 

Chamaebatia,  529 

Chamsecyparis,  411 

Chamaedorea,  466 

Chamaerops,  465 

Chamomile,  514 

Channels  in  Cell- Walls,  24 

Chaptalia,  512 

Chara,  14,  333,  334 

Characese,  271,  331,  335,  337 

Charese,  333,  334 

Charlock,  554 

Check  erberry,  510 

Cheiranthus,  554 

Chelura,  524 

Chemical  Processes  in  Cells,  168 

Chemical  Processes  in  the  Plant 

178 

Chemical  Rays  of  Spectrum,  192 
Chenopodiacese,  495 
Chenopodiales,  494 
Chenopodium,  71,  102,  436,  4!)5 


582 


GENERAL  TNDEX. 


Cherimova,  561 

Cherry,  62,  64,  126,  143,  159,  284, 

292,  426,  428,  436,  530 
Cherry  Blight,  140 
Cherry  Laurel,  173 
Chestnut,  58,  154,  421,  478 
Chibou,  540 
Chicory,  512 
Chimaphila,  510 
China  Aster,  516 
China  (irass,  491 
Chinese  Date,  506 
Chinese  Primrose,  506 
Chinese  Sugar-Cane,  457 
Chinese  Yam,  467 
Chiodecton,  310 
Chionanthus,  505 
Chittagong  Wood,  540 
Chlaenacese,  547 
Chlamydospores,  237 
Chloranthacese.  483 
Chlorides,  176 
Chlorine,  175 
Chlorococcum,  219 
Chlorophyll.  50,  70,  94,  155,  178, 

191,  205,  206 
Chlorospermese,  337 
Chlorosporese,  339 
Chloroxylon,  540 
Chocolate,  546 
Chocolate  Tree,  545 
Chondrites,  278 
Chondrus,  277 
Choripetalae,  476,  518,  568 
Choripetalous,  431 
Chorisepalous,  431 
Chowlee,  532 
Chronizoospores,  223 
Chroococcacese,  210,  305,  306,  338 
Chroococcus,  216 
Chroolepidese,  306 
Chrysanthemum,  514 
Chrysobalaneue,  530 
Chrysophyllum,  506 
Chufa,  457 
Churrus,  488 
Chylocladiea?,  277 
Chytridiacese.  339 
Cichoriacese,  67,  77,  78,  119,  512 
Cichorium,  512 
Cicinnus,  429 
Cicuta,  520 
Cilia,  10 
Ciliary  Movement,  10 


Cinchona,  17,  64,  182,  517 

Cineraria,  514 

Cinnamomum,  494,  564,  565 

Cinnamon,  494 

Circinella,  237 

Circumcissile  Drhiscence,  435 

Circulation  of  Protoplasm,  14 

Cissus,  482,  538,  565 

Cistaceje,  552 

Cistus,  552 

Citric  Acid,  64,  182 

Citron,  541 

Citrullus,  522 

Citrus,  541 

Cladonia,  306,  309 

Cladoniei,  309 

Cladophora,  10,  37,  224,  245,  306 

Cladoxylon,  415 

Classification,  202 

Clavaria,  330 

Claviceps,  289,  294 

Claytonia,  199,  549 

Cleavers,  517 

Cleistogamous  Flowers,  421 

Clematis,  564 

Cleome,  552 

Clerodendron,  498 

Clethra,  510 

Cliftonia,  539 

Clirnacosphenia,  231 

Climacium,  360 

Climbing  Bittersweet,  539 

Closed  Bundle,  121,  443 

Closing  of  Flowers,  199 

Closterium,  11,  227 

Clove  Pink,  93,  550 

Clover,  197,  428,  532 

Cloves,  523 

Clove  Tree,  523 

Cluster  Cups,  316 

Cnicus,  513 

Coagulation  of  Albuminoids,   188 

190 

Coalescence  of  Floral  Organs,  432 
Coats  of  Ovule,  401 
Cobsea,  503 
Cob-nuts,  477 
Cocconeis,  230 
Cocconidese.  230 
Cocculus,  560 
Coccus,  490 
Cochineal  Insect,  520 
Cockleburs,  515 
Cockscomb,  496 


GENERAL  INDEX. 


5.83 


Cocoa,  546 

Cocoanut,  464 

Cocoineaa,  464 

Cocos,  464 

Cceloblastese,  250,  269,  336,  337 

Ccelogyne,  471 

Ccenobia,  221 

Coeoojroniei,  310 

Ccenogoniimi,  310 

Coffea,  517 

Coffee,  182,  517 

Cohorts  of  Dicotyledons,  476 

Cohorts  of  Monocotyledons,  453 

Coix,  93 

Colchicum,  460 

Coleochaetacese,  339 

Coleochaete,  271,  274,  279,  335,  337 

ColeochEeteaa,  340 

Coleus,  52,  498 

Collar,  475 

Collateral   Bundle.    120,  362,  368, 

380,  392,  438 
Colleina,  295,  298,  300,   301,   COS, 

306,  309 

Collemacese,  305,  339 
Collemei,  309 
Collenchyma,  29,  70,  89,  134,  363, 

378,  392 
Coll  urn,  475 
Colocyntli,  522 
Coloring  Matters,  64 
Colors  of  Flowers,  53 
Columbine,  564 
Columella.  210,236,  360 
Columelliaceas,  499 
Columelli ferae,  211 
Colza.,  554 
Comamlra,  476 
Combretaceae,  524 
Commelynaceae,  457 
Cominelynales,  457 
Common  Bundles,  368,  392,  438 
Comose  Seeds,  437 
Compass  Plant,  103,  156,  515 
Complete  Flower,  431 
Composite,  62,  94,  99.  197,  284,  435, 

429,  434.  512 
Composites,  153, 158 
Compound  Leaves,  147 
Compound  Pistil,  433 
( 'ompound  Raceme,  42-3 
Compounds  in  Plant-Food,  17(5 
Compound  Spike,  428 
Compound  Umbel,  428 


Concentric  Bundle,  120,  362 

Conceptacles,  265 

Concluding  Observations,  566 

Conducting  Tissue,  89 

Cone,  397 

Conepia,  531 

Conferva,  37,  306 

Confervacwe,  224,  245,  277,  339 

Conferva?,  340 

Confervites,  242 

Conjugate,  225,  242,  336,  340 

Conjugation,  45,  47,  225 

Conia,  162 

Conidia.   39,    241,   260.    273,    279. 

289.  292,  294,  312,  315,  323,  357 
Coniferse,  25,  51,  130,  132.  396,  409, 

410,  415 

Conifers,  143,  153,  158,  409,  410 
Coniocybe,  310 
Coniomycetes,  338 
Conium,  182,  520 
Connaraceae,  534 
Connarus,  534 
Connecting  Tube,  276 
Connective,  433 
Conotrema,  309 
Constituents  of  Plants,  106 
Convallaria,  460 
Conversion  into  Mucilage,  35 
Convolvulaceae,  77,  502 
Convovulus.  502 
Copaifera,  533 
Copaiva  Balsam,  533 
Copai-ye  Wood.  550 
Coperuica,  464 
Coprinus,  329,  330 
Coquilla-nuts,  464 
Corallina.  277.  278 
Coral  lineaa,  277.278 
Corallorhiza,  192,  471 
Corchorus,  545 
Cordate  Leaves,  146 
Coreopsis,  514 
Coriander,  520 
Coriarieae,  534 
Cork,  125.  480 
Cork  Cambium.  126 
Cork  Oak.  125,  480 
'ork-wood,  547 
Conn,  136 

Cormophyta,  203,  205 
Cormophytes,  335 
Cornaceae,  518,  565 
Corn  Cockle,  550 


584 


GENERAL   INDEX. 


C'ornua,  518,  565 
Corolla,  418,  430 
Corpuscula,  393,  402 
Cortex,  201 
Corylese,  477 
Corylus,  477,  564 
Corymb,  428 
Coryphineae,  464 
Coscinodisceae,  231 
Coscinodiscus,  11,  281 
Cosmarium,  44,  227 
Cotton,  98,  437,  546 
Cottonwood,  487 
Cotyledon,  526 

Cotyledons.  386,  391,  404,  424 
Couma,  504 
Cowslip,  506 
Cow  Tree,  489 
Crab-Apples,  527 
Cranberry,  511 
Crape  Myrtle,  523 
Crass  ul  a,  526 
Crass  ul  ace* ,  526 
Crategus,  527,  565 
Cratoxylon,  549 
Crayfislies,  growths  on,  257 
Cremocarp,  436 
Crenate  Leaf,  147 
Creosote  Busb,  543 
Crescentia,  499 
Cribraria,  211 
Crocus,  56,  468 
Crossosoina,  562 
Crotallaria,  532 
Croton,  484,  485 
Croton  011,484 
Crown  Imperial,  460 
Crucibulum,  325,  326 
Cruciferse.  98,  181,  264,  425.  553 
Crucifer  Family,  553 
Cryptogam,  204,271,  316 
Cryptogamia,  204,  205 
^Oyptomeria,  411 
Cryptonemieae,  277 
Crypto-Raplridieae,  231 
Crystalloids,  57.  58 
Crystals,  57,  59 
Cuba  Bast,  547 
Cubebs,  484 
Cuboidal  Cell,  19 
Cucumber,  522 
Cucumber  Tree,  561 
Cucumis,  14,  80.  522 


Cucurbita,  11,  13,  14,  35,  53,  80,85, 

522 
Cucurbitaceae,  29,  51.  71,  120.  181, 

521 

Cucurbitaria,  294 
Cultures  of  Lichens,  307 
Cultures  of  Moulds,  239 
Cultivated  Plants,  182 
Cummin,  520 
Cupania,  537 
Cupbea,  523 
Cupresseae,  411 
Cupressus,  409,  411 
Cups,  136 

Cupulifere,  425,  426,  477,  564 
Curare,  503 
Curcuma,  472 
Currant,  64,  526 
Cuscuta,  56,  502 
Cusparu-ae,  542 
Custard  Apple,  561 
Cuticle,  34,  93 
Cuticularizinjr,  35 
Cyanophyceae,  215,  336 
Cyathea,  377 
Cyatheaceae,  376 
Cycadeae,  409,  410 
Cycads,  409.  410,  416 
C'ycas,  399,  410 
C'yclamen,  506 
Cyclic  Flowers,  420,  430 
Cyclotella,  231 
Cydonia,  527 
Cylindrical  Cell,  19 
Cymatopleura.  231 
Cymbella,  230 
Cymbelleje,  230 
Cyme,  429 
Cymo-Botrys,  429 
Cymose  Inflorescence,  427,  42& 
Cymose  Mouopodium,  140 
Cynara,  572 
Cynaroideae,  512 
Cynips,  479 
Cynoglossum,  57 
Cynornorium,  476 
Cyperaceae,  457,  473 
Cyperus,  457 
Cypress,  411 
Cypripediese,  469 
Cypripedium,  469 
Cyrilla,  539 
Cyrillaorse,  539 


GENERAL  INDEX. 


585 


Cystidia,  328,  330 
Cystoliths,  60 
Oystopteris,  377 
Cystopus,  39,  260,  264 
Cytisus,  85,  532 

Dacrymyces,  289 

Dactylina,  308 

Dactyl  is,  455 

Daffodil,  468 

Dahlia,  62,  514 

Daisy,  516 

Dalbergia,  532 

Dammara,  413 

Dammar  Resin,  413 

Dansea,  378 

Dandelion,  512 

Dantzic  Fir,  412 

Daphnales,  491 

Daphne,  492 

Darlingtonia,  182,  557 

Dasya,  277 

Date,  germination  of,  453 

Date  Palm,  465 

Datisca,  521 

Datiscaceas,  521 

Datura,  102,  502 

Daucus,  519 

Daughter  Cells,  39 

Day  Lily,  460 

Deadly  Nightshade,  502 

Death  from  high  temperature,  188 

Death  from  low  temperature,  189 

Decandrous,  432 

Dehiscence,  435 

Dehiscent,  435 

Delesseria,  277,  278 

Delphinium,  106,  564 

Dendrobium,  471 

Dentate  Leaf,  147 

Denticella,  11 

Deoxidization  in  Assimilation,  179 

Dermatogen,  161,  423 

Desmidiacese,  44,  225,  242,  336,  338 

Desmids,  225 

Desmobacteria,  213 

Desmodium,  196,  198,  436,  53:5 

Determinate  Inflorescence,  428 

Deutzia,  526 

Diadelphous,  432 

Diulypetalous,  431 

Diandrous,  432 

Dianthus,  93,  550 

Diapensiaceae,  508 


Diarthrodaclyleae,  334 
Diatoma,  227,  231 
Diatomacese,  53,  227,  242,  336,  838 
Diatoineae,  340 
Diatoms,  34,  227,  242 
Diatrype,  294 
Dicarpellary,  433 
Dicentra,  556 
Dichasium,  429 
Dichlamydeous,  431 
Dichogamous,  434 
Dichotomy,  382 
Dichotomous  branching,  139 
Dichotomous  Cyme,  429 
Dicksonia,  378 
Diclinous  Flowers,  431 
D5cotyledones,393,  473,  568 
Dicotyledons,  93.  118,  123, 143, 148, 
150,  161,  200,  391,  416,  569,  570 
Dicranum,  360 
Dictamnus,  130, 132,  542 
Dictydium,  211 
Dictyotaceae,  339 
Didymium,  9,  10  188,  210,  432 
Diervilla,  518 
Diffusion,  174 
Digitalis,  500 

Digitately  lobed  leaves,  147 
Digitately  compound  leaves,  148 
Digynous,  433 
Dill",  520 
Dillenia,  562 
Dilleniaceae,  562 
Dimensions  of  cells,  17 
Dimerous,  430 
Dimorphandra,  533 
Dimorphous,  434 
Difficious,  249 
Dioacious  Flowers,  431 
Dionaea,  182, 197,  198, 526 
Dioscorales,  467 
Dioscorea,  467 
Dioscoreaceae,  467,  473 
Diosma,  543 
Diosmese,  542 
Diospyros,  506,  564,  565 
Dipetalous,  432 
Diplostemonous,  433 
Diplostephanae,  334 
Dipsacese,  516 
Dipsacus,  99,  516 
Dipterocarpese,  547 
Dirca,  492 
Direction  of  Spirals,  8$ 


586 


GENERAL   INDEX. 


Dirina,  309 

Discomycetes,  286,  338 

Disepalous,  431 

Distribution  in  Time,  568 

Disturbance  of  the  Equilibrium  of 
Water,  168 

Diurnal  Positions  of  Leaves,  199 

Division  of  Cells.  86 

Divisions  of  the  Vegetable  King- 
dom, 205 

Docks,  497 

Dodder,  53,  56,  502 

Dodecandrous,  432 

Dodecatheon,  506 

Dodonaese,  535 

Dogbane  Family,  504 

Dogwood,  518,  539 

Dogwood  Family,  518 

Dormant  Buds,  144 

Doryphora,  494 

Double  Cocoa-Nut,  465 

Doubly  Compound  Leaves,  148 

Douglas  Spruce,  33,  411 

Doum  Palm,  465 

Draba,  98,  264 

Dracaena,  444,  460 

Dracophyllum,  510 

Dragon  Trees,  444,  460 

Dragon's  Blood,  466 

Drosera,  182,  198,  429,  526 

Droseraceae,  526 

Drupaceous  Fruits,  436 

Drupaceous  Seeds,  437 

Drupe,  436 

Dry  Fruits,  435 

Dryobalanops,  547 

Duckweeds,  461 

Dudresnaya,  276,  277 

Dogttetia,  561 

Dulse,  277 

Dumontieae,  277 

Doric,  547 

Dwarf  Almond,  530 

Dwarf  Palmetto,  465 

Dyers'  Weed,  552 

Earth-Star,  324, 326 
Ebenaceaj,  505,  564,  565 
Eb»;nales,  505 
Ebony,  506 
Ebony  Family,  505 
Ecbalium,  11,  81 
Echinocystis,  74,  81,  522 
Echites,  504 


Ectocarpese,  339 

Ectoplasm,  4,  15 

Edible  Hymenomycetes,  330 

Eel  Grass,  473 

Egg  Plant,  500 

Elaeagnaceae.  491 

Elaeagnus,  492 

Elseis,  464 

Elaphomyres,  286 

Elaters,  348,  367 

Elatinaceae,  549 

Elder,  71,  126, 144,  518 

Elecampane,  516 

Elements  of  Plant  Food,  175 

Eleutheropetalous,  431 

Elliptical  Leaves,  146 

Elm,  61,  64,  143,  146, 187,  488 

Elm  Family,  488 

Embryo,  46,  391,  404,  423 

Embryology,  204 

Embryonic  Vesicle,  47 

Embryo-sac,    11,    41,    46,  66,   137, 

389,  401,  402,  420 
Encephalartos,  410 
Endive,  512 
Endocarp,  535 
Endocarpei,  310 
Endocarpon,  310 

Endochrorne,  227 

Endogenae,  451 

Endoplasm,  4,  16 

Endosperm,  11,  41,  390,  402,  403, 
420,  423,  425 

Endospore,  34,  257,  263,  342 

English  Bean,  38,  531 

English  Ivy,  519 

English  Walnuts,  480 

Enneandrous,  432 

Ensiform  Leaf  of  Iris,  159 

Entomophilous  Flowers,  421 

Epacrideae,  508,  510 

Epacris,  510 

Ephebe,  305.  309 

Ephedra,  413,  416 

Epidendreae,  470 

Epidendrum,  470 

Epidermal    System,    90,   357,  8«W, 
406 

Epidermis,  91,   92.   162,  170,  301, 
343,  862,  367,  392,  487 

Epigaea,  510 

Epigynoua,  4'-'A 

Epigyny,  434 

Epilobium.  61.522 


GENERAL  INDE*. 


58? 


Kp  nasty,  199 

Epipetalous,  438 

Epispore,  257,  263 

E  pit  hernia,  231 

Equilibrium  of  Water,  168 

Equisetacese,  35,  143,  368,  389 

Equisetinse,  362,  363,  382 

Equisetites,  369 

Equisetum,  11,  37,  80,  81,86,  88, 

110,  115,  120,  123,  128,  303,  368, 

369 

Erect  Ovules,  433 
Ergot,  289,  295 
Erica,  510 

Ericaceae,  508,  564,  565 
Ericales,  508 
Ericineae,  508,  509 
Erigeron,  98 
Eriocaulonaceae,  457 
Erodium,  543 
Erysimum,  437 
Erysiphaceae,  140,  278,  339 
Erysiphe,  279,  383 
Erysiphei,  283 
Eryih rosy Ion,  544 
Eschschoitzia,  556 
Essence  of  Cinnamon.  63 
Essence  of  Wintergreen,  (>3 
Essential  Oils,  62 
Ethiopian  Lily,  462 
Etiolated  Plants,  52 
Euastrum,  227 
Eucalyptus,  94,  524,  565 
Eudorina,  243 
Eujrenia,  523 
Euglena,  50 
Eunotia,  231 
Euonymus,  539 
Eupatoriaceae,  516 
Eupatorium,  264,  516 
Eupodiscese,  231 
Eupodiscus,  231 
Euphorbiaceae,  76,  77,  425,  484 
Euphorbiales,  484 
Euphorbia,  78,  102,  150,  485 
Euphorbium,  Gum,  484 
Eurotiuin,  281,  285,  289 
Evaporation    of    Water,  167,  169, 

185, 191 

Evening  Primrose,  61 
Everlasting  Flowers,  515 
Evernia,  308 

Exalbuminous  Seeds,  391,  437 
Excretions,  61 


Exco3caria,  485 
i  Exhalation  of  Water,  169 
Exocarp,  435 
Exogenae,  473 
Exospore,  34,  222,  342 
Extiiie,  34 
Extrorse  anthers,  433 

Fagopyrum,  496 

Fagus,  17,  150,  479,  564 

False  Flax,  554 

False  Raceme,  429 

Families  of  Cells,  65 

Farfugium,  514 

Fennel,  520 

Fermentation,  212 

Fermentive  Changes,  190 

Ferns,  123,  143,  155,  362,  370,  371, 

872,  373 
Fertilization  in  Angiosperms,  419, 

422 

Ferula,  520 
Fever  Tree,  517 
Fibrous  Roots,  165 
Fibrous  Tissue,  74,  89,   106,  112, 

119,  123,  363,  368,  392 
Fibro-vascular  Bundles,   106,  155, 

159,  352,  362,  367,  392.  407,  438 
Fibro- vascular  System,  90, 106,343, 

359,  362,  438" 
Ficoidales,  520 
Ficoideae,  520 

Ficus,  94,  102,  489,  564,  565 
Field  Bean,  475,  531 
Field  Oak,  480 
Fig,  61,  62,  437,  489 
Figwort  Family,  500 
Filament,  394,  418 
Filbert,  477 

Filices,  370,  371,  372,  373,  389 
Filicina;,  369,  382,  389 
Fishes,  growths  on,  257 
Flagellarieae,  457 
Flax,  35,  181,  187,  188,  491,  543 
Flax  Family,  543 
Fleshy  Fruits,  435 
Flies,  growths  on,  257 
Floral  Envelopes,  136.  155 
Floral  Symmetry,  429 
Floridese.53, 186, 271,  273,  335,  337, 

339,  340 

Flower,  342,  353,  391,  394,  417 
Flower-axis,  136 
Flowering  Dogwood,  518 


588 


OEXKRAL   INDEX. 


Flowering  Plants,  203,  205 

Flowerless  Plants,  203,  205 

Flowers,  Colors  of,  53 

Flowers  in  darkness,  192 

Flow  of  Sap,  174 

Foeniculum,  520 

Foliage-leaf,  136 

Follicle,  436 

Fontinalis,  360 

Fool's  Parsley,  520 

Foot,  386 

Forget-me-not,  502 

Forked  Cyme,  429 

Forked  Cymose  Monopodium,  140 

Forked  Dichotomy,  139 

Formation  of  Alkaloids,  182 

Formation  of  Ice  Crystals,  189 

Formation  of  New  Cells,  36 

Forms  of  Cells,  18, 19 

Forms  of  Leaves,  146 

Forms  of  Roots,  165 

Forsytliia,  505 

Fossil  Characeae,  334 

Fossil  Cceloblastese,  254 

Fossil  Dicotyledons,  564 

Fossil  Florideae,  278 

Fossil  Fucaceje,  269 

Fossil  Gymnospenns,  415 

Fossil  Helvellace*,  289 

Fossil  Hymenomycetes,  331 

Fossil  Lichens,  310 

Fossil  Monocotyledons,  473 

Fossil  Protophytes.  219 

Fossil  Pyrenomycetes,  295 

Fossil  Zygosporeae,  242 

Four  O'Clock,  497 

Foxglove,  500 

Fragaria,  528 

Fragilaria,  227,  231 

Fragilariese,  231 

Framework  of  the  Leaf,  155 

Frank  eniaceae,  550 

Fraxinella,  540 

FraxinuB,  505,  565 

Free-cell  Formation,  42,  47,  49 

Free  Central  Placenta,  434 

Free  Oxygen,  179 

Fringe  Tree,  505 

Fritillaria,  460 

Frostweed,  552 

Fruits,  381,  426,  435 

Fruit  Sugar,  62 

Frullania,  341,  351 

Frustule,  227 


Fucacese,  35, 53, 135,  186,  243,264.. 

268,  269,  336,  337,  339,  340 
Fuchsia,  61,  93,  94,  102,  104,  522 
Fucoideae,  268,  269 
Fucoides,  269 
Fucus,  265,  268 
Fuligo.  2,  10,  188,  194,  210 
Fuller's  Teasel,  516 
Fumariaceae,  555 
Fumitory,  556 
Funaria,  352,  360 
Fundamental  System,  90,  123,  359, 

362,  363,  408,"  438 
Fungales,  337 
Fungi,  13,  39,  53,  56,  66,  67,  86,  90, 

192,  204,  "205,  337,  340 
Funkia,  13,  460 
Fusanus,  476 
Fusiform  Cell,  19 
Fustic,  490 

Galactodendron,  78,  489 

Galanthus,  468 

Gal  i  pea,  542 

Galium,  517 

Gamboge,  548 

Gainopetalae,  476,  497,  568 

Gamopetalous,  432 

Gamosepalous,  432 

Garcinia,  548,  549 

Garden  Balsam,  542 

Gardenia,  518 

Garlic,  61,  63,  458 

Gas  Plant,  540 

Gasteromycetes,  323,  324,  338,  33!  i 

Gaultheria,  510 

Gaylussacia,  511 

Geaster,  324,  326 

Geissolomese,  484 

Gelidieje,  277 

Gelidiuui,  277 

Gemmae,  344,  357 

Generalized  Forme,  133 

Generating  Spiral,  151 

Genetic  Relationship,  208 

Gentianaceae,  503 

Gentianales,  503 

Gentian  Family,  503 

Genuflexous  Conjugation,  234 

Georgia  Bark,  517 

Geotropism,  194,  200 

Geraniacese,  542 

Geraniales,  540 

Geranium,  543 


GENERAL   INDEX. 


589 


Geranium  Family,  542 

Gerardia,  53 

German  Ivy,  514 

Germ-cell,  341,  348,  362,  390,  420 

Germination  of  Dicotyledons,  474 

Germination    of    Monocotyledons, 

451 

Germination  of  Seeds,  181,  187,  404 
Gesuera,  499 
Gesneraceae,  499 
Giant  Puff-ball,  326 
Giant  Redwood,  411 
Giant  Silver  Fir,  412 
Gijrartineae,  277,  278 
Gilia,  503 
Gills,  328 
Gillyflower,  554 
Ginger,  472 

Gingerbread  Palm,  465 
Ginkgo,  81,  399,  409,  410 
Ginseng, 518 
Gladiolus,  468 
Glands,  137 

Glandular  Hairs,  97, 130 
Glandular  Scales,  97 
Gleditschia,  533 
Gleichenia,  374,  376 
Gleicheniaceae,  376 
Globe  Amaranth,  496 
Globe  Flower,  564 
Globoids,  57 
Gloeocapsa,  216 

Glossology  of  Angiosperms,  426 
Gloxinia,  499 
Glucose,  6-3,  180,  181 
Glumales,  45:'> 
Glycyrrhiza,  532 
Glyphidei,  310 
Glyi.his,  310 

Gnetaceae,  396,  401,  410,  413 
Gnetum,  413 
Golden  L'ly,  460 
Golden  Rod,  516 
Gompbonema,  229 
Gnmphonemaceae,  230 
Gotnphrena,  496 
Gonidia,   217,   218,    219,  295,  301, 

307 

Goodeniaceae,  512 
Gooseberry,  62,  64,  283,  436,  526 
Gordonia,  548 
Gossypium,  426,  546 
Gourd,  29,  184,  523 
Gourd  Family,  521 


Graminea?,  94, 129,322,  425,  453,473 

Grammatophora,  231 

Granulose,  55,  .r)6 

Grape,  62,  64,  264,  284,  288,  537 

Grape  Mildew,  264 

Grapevine,  61 

Graphidiacei.310 

Graphis,  301,  306,  310 

Grasses,  35,  93,  98,  102,  150,  187, 

195,  289,  295,  316,  323,  421,  429. 

436,  464 

Grass  Family,  453 
Gravitation  and  Geotropism,  194 
Great  Laurel,  510 
Greenheart  Tree,  494 
Green  Hellebore,  460 
Grevillea,  491 
Grindelia,  516 
Ground  Cherries,  500 
Ground  Tissue,  89,  123 
Grouping  of  Living  Things,  203 
Growing  Point,  87 
Growth  of  Cell-Walls,  22 
Guaiacum,  543 
Guavas,  523 
Guinea  Pepper,  461 
Gulf- Weed,  269 
Gum,  62,  63,  129 
Gumbo,  547 
Gummy  Substances,  96 
Gum  Acacia,  533 
Gum  Ammoniacum.  520 
Gum  Arabic,  6  J,  533 
Gum  Asa!o3tida,  520 
Gum  Benzoin,  505 
Gum  Copal,  533 
Gum  Canals,  129 
Gum  Euphorbium,  484 
Gum  Galbanum,  520 
Gum  Kino,  532 
Gum  Lac,  490 
Gum  Opopanax,  520 
Gum  Storax,  505 
Gum  Tragacanth,  63,  532 
Gunja,  488 

Gutta  Percha.  78,  506 
Guttiferse,  548 
Guttiferales,  547 
Gyalecta,  309 

Gymnocarpous  Lichens,  297,  298 
Gymnocladus,  533 
Gymnospermae,  393,  568 
Gymnosperms,  60,  80,  85,  118,  123, 

391,  393,  437,  569,  570 


590 


GENERAL   INDEX. 


Gymnosporangium,  314,  315,  317 

Gymnostemium,  469 

Gynandrous,  249.433 

Gynoecium,  419,  430,  433 

Gypsopbila,  550 

Gyroatonmm,  309 

Habenaria,  470 

Hackberry,  488 

Hsemantbus,  171.  4C8 

Haematoxylon,  533 

Haemodoraceae,  467 

Hairs,  90,  137 

Halesia,  505 

Halimeda,  254 

Halionyx,  231 

Halonia,  385 

Halorageae,  525 

Halosaccion,  277 

Hamamelaceae,  526 

Hamamelia,  526 

Haploatephanse,  334 

Hascbisch,  488 

Hauptplasma,  4 

Haustoria,  258,  279,  317 

Hautschicht,  4,  16 

Hawthorn,  428,  527 

Hazel,  187,  284 

Hazel  Nut,  477 

Head,  428 

Heads,  Racemose,  429 

Heads,  Spicate,  429 

Heath,  509 

Heath  Family,  508 

Heat-Raya  of  Spectrum,  192 

Hedeoma,  497 

Hedera,  103,  129,  165,  194,  519,  564 

Helenioideae,  514 

Heliamphora.  557 

Helianthemum,  552 

Heliantbus,  62,  102,  151,  284,  514 

Helianthoidea;.  514 

Helicbrysum,  516 

Helicoid  Cyme,  429 

Helicoid  Monopodium,  140 

Helicoid  Sympodial  Dicholomy,140 

Heliopelta,  231 

Heliopelieae,  231 

Heliotrope,  502 

Heliotropism,  193,  200 

Heliotropium.  502 

Helipterura,  515 

Hellebore,  563 

Helleborua,  563 

Helminthostacbys,  380 


Helvella,289 

Helvellacese,    28(5,   28  ,    291,   2U5, 

299,  339 

Hemerocallis,  159,  429,  460 
Hemiaulus,  231 
Hemicyclic  Flowers,  429 
Hemitelia,  377 
Hemlock,  520 
Hemlock  Spruce,  154,  411 
Hemp,  61,  188,  488 
Henbane,  502 
Henna,  523 

Hepatica,  147,  187,  563 
Hepaticae,  343,  361 
Heppia,  309 
Heptandroua,  432 
Herd'a  Graas,  455 
Hermapbrodite  Flowers,  431 
Hernandiwe,  492 
Hernioid  Protrusions.  30 
Hesperis,  554 
Heterocysts,  206,  217 
Heterodermese,  211 
Heteroecism,  314 
Heterogonous,  435 
Heteroijonous  Dimorpbous,  435 
Heterogonous  Trimorpbous,  435 
Heteromerous  Flowers,  430 
Heteromerous  Licbena,  295,  301 
Heterosporese,  372,  383 
Heterostyled,  435 
Heterotbeciuin,  310 
Heucbera,  106 
Hevea,  78,  485 
Hexaudrous,  432 
Hibiscus,  547 
Hickory,  144,  158,  482 
Hickory-nut,  73,  482 
I  Hieracium,  150 
I  Hilum  of  Starch.  53 
Hippomane.  485 
Hippuris,  88 
Holly,  94,  539 
Holly  Family,  539 
Hollyhock,  547 
j  Homology  and  Analogy,  120 
!  Homoomerous  Lichens,  295,  801 
:  Honey,  421 
!  Honey  Locust,  533 
|  Honeysuckle,  199,518 
,  Honesty,  554 
Hop.  61,  199,283,488 
Hop  Tree,  542 
Hordfum,  455 


GENERAL  INDEX. 


Horehound,  497 

Hornbeam,  477 

Horsechestuut,  58,  144,  42!»,  5:57 

Horserniut,  4«JS 

Horseradish,  63,  554 

Hottonia,  186 

Ilouseleek,  52(5 

Houstonia,  517 

Hoya,  61,  503 

Huckleberries,  511 

Hudsonia,  552 

Humiriaceae,  543 

HuuiuluB,  103,  488 

Hyacinth,  94, 102,  165,  460 

Hyacinthus,  4(50 

Hydimm,  328,  330,  S551 

Hydra,  50 

Hydrales,  473 

Hydrangea,  526 

Hydrocarbons,  63 

Hydrocharideae,  473 

Hydrodictyon,  65,  223 

Hydrogen,  175,  179 

Hydrophyllaceae,  502 

Hydrotliyria,  309 

Hygroscopic  Tissue,  157 

Hymenaea,  533 

Hymenium,  278,  286,  297,  323 

Hyuienophyllaceae,  376 

Hymenophyllum,  376 

Hymenomycetes,  289,  323,  326,  338, 

339 

Hyoscyamus,  502 
Hypericacese,  549 
Hypericum,  132,  433,  549 
Hyphse,  194,  235 
Hyphaene,  465 
Ilyphomycetes,  338 
Hypnea,  277 
Hypneae,  277 
Hypnum,  360 

Hypocotyledonary  Stem,  404 
Hypoderma,  72,  124 
Hypodermic,  338,  339 
Hypogynous,  434 
Hyponasty,  199 
Hypophysis,  424 
Hypoxylon,  294 
Hyssop,  497 
Hyssopus,  497 

Iberis,  441,  554 

Ice  Crystals,  formation  of,  189 

Iceland  Moss,  308 


Ice  Plant,  520 

Ilex,  539  565 

lliciueas,  539,  565 

Imbibatioii  power  of  Protoplasm, 

5,168 
Impatieiis,  14,  81,  85,  88,  159,  165, 

192,  264,  421,  542 
Incombustible  substances,  35 
Incomplete  flower,  4:jl 
Incumbent  cotyledons,  437 
Indehiscent,  435 
Indeterminate  inflorescence,  428 
Indian  Corn,  52,  56,  57,  59,  63,  70, 

106,  113.  114,  131,  155,  157,  165, 

166,  187,  318,  323,  451,  455,  522 
Indian  Turnip,  61,  428 
Indian  Pipe,  511 
India  Rubber,  78,  485 
Indigo,  532 
Indigofera,  532 
Individual  development,  204 
Indus! um,  374 
Inflorescence,  427 
Innate  Anthers,  433 
Insect  agency  in  Pollination,  421 
Insects  killed  by  parasitic  plants, 

294 

Integument  of  ovule,  401 
Intercalarv   growth   of    cells,    22, 

140,  246 

Intercellular  canal,  114,  409 
Intercellular  spaces,   70,  99,    128, 

156, 167,  171,  197 
Intercellular  substance,  35,  68 
Interfascicular  cambium,  408 
Intermediate  tissue,  125 
Internal  cell-formation,  36,  39 
Internal  structure  of  Leaves,  155 
Inline,  34 

Intrafascicular  Canal,  111 
Introrse  anthers,  4<!3 
Intussusception,  31,  54 
Inula,  62,  516 
In uline,  62,180 
Inuloideae,  515 
lonidium,  551 
Ipecacuanha,  517,  551 
Ipomoea,  14,  53,  70,  502 
Iridaceae,  468 
Iris,  61,  102,  157,  158,  468 
Iris  Family,  468 
Irish  Moss,  277 
Iron,  175 
Iron  Bark  Tree,  524 


892 


GENERAL   INDEX. 


Iron  Salts,  176 

Iron- weed,  516 

Irouwood,  284,  477.  505,  539 

Irregular  dehiscence,  435 

Irregular  flowers,  431 

Isatis,  554 

Isoeteie,  383,  387,  389, 391 

Isoetes,  382,  388,  403 

Isomerous  flowers,  430 

iHonandra,  506 

Isosporae,  372,  383 

Jsostemonous,  432 

Isthmia,  231 

Ivory  Nut,  463 

Ivy,  98,  129,  165,  194,  519 

Ixora,  518 

Jack  Fruit,  489 

Jalap,  502 

Jamaica  Cedar,  540 

Jamaica  Ginger,  473 

Jamaica  Hose  wood,  505 

Japanese  Wax,  535 

Japan  Lacquer,  535 

Japan  Lily,  460 

Jarool,  523 

Jar  rah,  524 

Jasininuin,  505 

Jatroplia,  484 

Jerusalem  Artichoke,  515 

Jessamine,  505 

Joint-Firs,  410,  413 

Jonquil,  468 

Judas  Trees,  533 

Juglandaceae,  480,  564 

Juglans,  102,  480,  565 

Jujube,  539 

Juncaceae,  457 

Juncus,  131 

Jungermannia,  150,  349,  351 

Jungermanniace*.   345,    347,  351, 

358 

Juniperus,  17,  81,  410,  411 
Justicia,  499 
Jute,  545 

Kaki,  506 
Kale,  553 
Kalmia,  510 
Kapor,  547 
Kaulfussia,  379 
Kauri  Pine,  413 
Kentucky  Blue  Grass,  455 
Kentucky  Coffee  Tree,  533 


Khenna,  523 
Knijrhtia,  491 
Koelreuteria,  537 
Kohl  Rabi,  554 
Kuhne's  Experiment,  S) 

Labiate,  71,  132,  41)7 

Laburnum,  532 

Lace-Bark  Tree,  493 

Lacistemacese,  484 

Lacquer,  535 

Lactuca,  512 

Lactucarium,  512 

Lady's  Slipper,  409,  543 

Laelia,  471 

Laevulose,  62 

Lagenaria,  522 

Lagetta,  493 

Lagerstroenria,  523 

Lambkill,  510 

Lamella?  of  Cell-wall,  68 

Lamiales,  497 

Laminaria,  268 

Laminariaceae,  339 

Lamioarites,  269 

Lanceolate  Leaves,  146 

Lance  Wood,  561 

Lantana,  498 

Laportea,  491 

Larch,  185,  412 

Larix,  81,  409,  411,  412 

Larkspur,  564 

Larrea,  543 

Lateral  Buds,  143 

Lateral  Conjugation,  234 

Lateral  Stems,  142 

Latex,  76 

Laticiferous   Tissue,    67,   76,    106 

119,  124,  363,  392 
Lathrsea,  56 
Latliyrus,  532 
Latticed  Cells,  17,  79,  111 
Lauraceaa,  493,  565 
Lau  rales,  493 
Laurel,  493,  510 
Laurel  Family,  493 
Laurel  ia,  494 
Laurus,  493,  564,  565 
Lavandula,  497 
Lavender,  497 
Lawsouia,  523 
Layers  of  Cell-wall,  34 
Lead-pencil  Wood,  411 
Leaf.  136,  144,  197,  265,  369 


GENERAL  INDEX. 


593 


Leaf-forms,  146 
Leaflet,  147 
Leaf -stalk,  145 
Leaf-tissue,  155 
Lecanactidei,  310 
Lecanactis,  301,  310 
Lecanora,  309 
Lecanorei,309 
Lecidea,  310 
Lecideacei,  309 
Lecideei,  310 
Leek,  61,  458 
Left,  To  the,  199 
Legume,  436 

Leguminosse,  426,  531,  565 
Leguminosites,  565 
Lejeunia,  351 
Lejolisia,  274,  277 
Lemaniaceae,  339 
Lenma,  165 
Lemnaceae,  461 
Lemon,  64,  130,  132,  547 
Lemon  Verbena,  498 
Lennoaceae,  508 
Lentibulariacese,  499 
Lenticels,  126,  532 
Lenzites,  331 
Leonia,  552 

Lepidium,  188,  264,  425,  554 
Lepidodendreae,  385 
Lepidodendron,  385 
Lepidophloios,  385 
Lepidostrobus,  385 
Leptogium,  295,  306,  309 
Lessonia,  268 
Lettuce,  512 
Leucadendron,  491 
Leucobryum,  351 
Leucojum,  468 
Leucopogon,  510 
Leucosporeae,  339 
Lever- wood,  478 
Liatris,  429,  516 
Libocedrus,  411 
Licania,  531 
Licea,  211 
Licbenales,  337 
Licbenes,  295,  337,  339 
Lichens,  217,  218,  295,  338 
Licbina,  309 
Ligbt,  169,  190,  197 
Lignification,  35 
Lignum-vitae,  543 
Ligule,  383,  386 


Ligustrum,  505 

Lilac,  102,  126, 144,  158,  159,  284. 

505 

Lilac  Bligbt,  140 
Liliacese,  94,  425,  458,  473 
Liliales,  457 
Lilium,  102,  460 
Lily,  94,  102,  460 
Lily  Family,  458 
Lily-of-tbe- Valley,  61,  460 
Lima  Bean,  532 
Lime,  64,  541 
Lime  Salts,  176 
Lime  Tree,  545 
Limits  of  Temperature,  184 
Limnoria,  498 
Linaceae,  543 
Linaria,  318 
Linden, 146,  545 
Linden  Family,  545 
Linear  Leaves,  146 
Linen,  544 
Linn,  545 
Linociera,  505 
Linseed  Oil,  62,  544 
Linum,  543 
Liparis.  471 
Lippia,  498 
Liquidamber,  526 
Liquorice,  532 

Liriodendron,  72,  85,  562,  564 
Litcbi,  537 

Litbospermum,  421,  436 
Litmus,  308 
Live-forever,  526 
Live-leaf,  526 
Live  Oak,  479 
Liver-leaf,  187 

Liverworts,  91,  341,  343,  351,  356 
Loasaceae,  522 
Lobelia,  511 
Lobeliaceae,  77,  511 
Lobes  of  Leaves,  147 
Loblolly  Bay,  548 
Loculicidal  Deliisceuce,  435 
Locust  Tree,  61,  532,  533 
Lodoicea,  465 
Loganiaceae,  503 
Logwood,  533 
Lombardy  Poplar,  487 
Loment,  436 
Lomentaria,  277 
Longan, 537 
Long-flowered  Lily,  460 


594 


GENERAL  INDEX. 


Long  Moss,  47 

Longitudinal  Tension,  201 

Lonicera,  518 

Loranthacese,  477 

Love  Flower,  460 

Love-in-a-Mist,  564 

Lucerne,  166,  532 

Luffa,  522 

Lunaria,  554 

Lupine,  58,  59,  532 

Lupin  us,  582 

Lupulin,  488 

Lychnis,  550 

Lychnothamnus,  334 

Lycium,  502 

Lycogola,  10 

Lycoperdaceae,  339 

Lycoperdon,  324,  325 

Lycopersicum,  500 

Lycopodiacese,  80,    123,  383,   384. 


Lycopodinje,  362,  382,  389 
Lycopodium,  81,  112,  121,123, 150, 

382,  384,  385 
Lygodium,  374,  377 
Lysiloma,  534 
Lysiinacliia,  50ff 
Lythraceaj,  522 
Lythrum.  523 

Mace,  494 
Madura,  102.  490 
Macrocystis,  268 
Macrogonidia,  219 
Macrosporangiu,  373,  382,  386 
Macrospores,    362,   371,   373,   381, 

382,  386,  389,  403 
Macrozamia,  410 
Macrozoogonidia,  223 
Madder,  518 
Madeira  Vine,  495 
Madrona,  509 
Magnesia  Salts,  176 
Magnesium,  175 

Magnolia,  426,  437,  561,  56-1    r>(}5 
Magnoliaceaj,  561,  565 
Magnolia  Family,  561 
Mahogany,  524.  540 
Mahonia.  559 
Maize,  455 
Malaxidese,  471 
Malax  is,  471 
Malay  Apple,  523 
Malic  Acid,  64,  182 


Mallotium,  301,  306 

Mallow,  144,  147, 547 

Mallow  Family,  546 

Malpighiacese^  543 

Malva,  85,  547 

Malvaceae,  98,  546 

Malvales,  544 

Mammea,  549 

Mammee  Apple,  549 

Mamillaria,  151 

Mauchineel  Tree,  485 

Mangel  Wurtzel,  495 

Mangifera,  535 

Mango,  535 

Mangosteen,  548 

Mangrove  Tree,  524 

Manihot,  484 

Manilla  Hemp,  472 

Manzanita,  156,  509 

Mauubrium,331 

Maple,  77, 145,  147,  187.  284,  535 

Maranta,  473 

Marattia,  379 

Marattiacese,  363,  372.  378,  380 

Marchantia,  14,344,  347,  348,  351 

Marchantiacese,  91,35C 

Marigold,  514 

Marmalade,  506 

Marrubium,  497 

Marsilia,  381,  382 

Marsiliacese,  382 

Marty ni a,  98,  197,  499 

Marvel  of  Peru,  497 

Mastic,  535 

Mastigonema,  218 

Mastigonia,  231 

Mate,  540 

Mathematical  Gymnastics,  152 

Matthiola,  554 

Matisia,  547 

Maurandia,  500 

Maximum  Light,  191 

Maximum  Temperature,  184 

Mayaceae,  457 

May  Apple,  437,  559 

Mayflower,  187,  510 

Meadow  Grass,  166.  185 

Meadow  Saffron,  4<iO 

Meconic  Acid,  182 

Medicago,  532 

Medullary  Rays,  408,  449 

Melaleuca,  150 
Melamho  Bark,  485 


GENERAL   INDEX. 


595 


Melampaora,  314,  315 

Melanospermeae,  268,  337 

Melaspilea,  810 

Melastomacete,  523 

Melia,  540 

Meliaceae,  540 

Meliantheae,  535 

Melicocca,  537 

Melobesiacese,  339 

Melon,  522 

Melosira,  231 

Melosirese,  231 

Members  of  the  Plant  Body,  133 

Menispermaceae,  560 

Menispermum,  560 

Mentha,  497 

Menzies'  Spruce,  412 

Mericarp,  436 

Merismopedia,  216 

Meristeni,  86,  168 

Meroxylou ,  532 

Mescal,  468 

Mesembryanthemum,  520 

Mesocarp,  435 

Mesocarpeae,  235,  241,  242 

Mesocarpus,  235,  238 

Metasperrnse,  393 

Metastasis,  62,  179,  186,  192 

Micrasterias,  227 

Microbacteria,  213 

Micrococcus,  213 

Microgonidia,  219,  304 

Micropyle,  391.  419 

Micro8pha3ra,281,  283 

Microsporangia,  372,  382,  386,  390, 

402,  418 
Microapores,  362,371,  372,381,  382, 

386,  389 

Mignonette,  428,  552 
Mikania,  516 
Mildew,  Grape,  264 
Milkweed  Family,  503 
Mimosa,  197,  198,  534 
Mimoseae,  533 
Mimosites,  565 
Mimulus,  197,  500 
Minimum  Light,  191 
Minimum  Temperature,  184 
Miut  Family.  497 
Mirabilis,  497 
Mistletoe,  53,  94.  182,  477 
Mistletoe  Family,  477 
Mitella,  106 
Mitchella.  517 


Mixed  Inflorescence,  428,  429 
Mnium,  353,  360 
Mock  Orange,  526 
Modes  of  Branching,  139 
Molecules  of  Cell-wall,  32.  167 
Mollu<ro,  520 
Monadelphous,  432 
Monandrous,  432 
Monarthrodactylae,  334 
Monera,  15,  207 
Monimiaceae,  494 
Monizia,  520 
Monkey  Flower,  500 
Monkey  Pot,  524 
Monkshood,  562 
Monocarpellary,  433 
Monochasium,  429 
Monochlamydeous,  431 
Monoclinous  Flowers,  431 
Monocotyledones,  393,  451,  568 
Monocotyledons,  88,  93,  123,  143, 

161,  318,  391,  416,  451,  569,  570 
Monocyclic,  430,  432 
Monoecious,  249,  431 
MonogyncBcial  Fruit*,  436 
Monogynous,  433 
Monomerous,  430 
Monopetalous,  431,  432 
Monopodial  Branching.  133 
Monosepalous,  431.  432 
Monosymmetrical  Flowers,  431 
Monotropa,  192,  511 
Monotropea?,  508.  510 
Monterey  Cypress,  411 
Moonseed,  560 
Moosewood,  492 
Mora  Tree,  533 
Moraceae,  488,  565 
Morchella,  289 
Morel,  289 
Moringeae,  534 
Morning  Glory,  53,  199,  502 
Morphia,  182,  556 
Morphological  Resemblances,  202 
Morphological  Unit,  20 
Morphology,  Special,  202 
Morus,  490 
Mosses,  46,  86,  92,  137.  143,  145, 

155,  194,  200,  341,  343,  351,  382 
Mother-cells,  39 
Moulds,  194,  235,  285.  288 
Mountain  Ash,  64,  201 
Mountain  Bay,  548 
Mountain  Mahogany,  529 


596 


GENERAL   INDEX. 


Movement  of  Water,  172 
Movements  due  to  External  Stim- 
uli, 197 

Movements  of  Nutation,  199 
Movements  of  Plants,  196 
Movements  of  Protoplasm,  6,  196 
Movements  of  Torsion,  200 
Mucilage,  35 
Mucor,  212,  236,  241 
Mucoraceae,  338 
Mucorini,  235,  242,  336 
Mublenbergia,  455 
Mulberry,  61,  437,  490 
Mulberry  Family,  488 
Mullein,  98,  500 
Mullein  Pink,  550 
Multilocular,  433 
Mummy-clotb,  544 
Musa,  472 
Musa,  472 
Musci.343,  351 
Muscites,  360 
Musbrooin,  328,  330 
Musk  Tree,  516 
Mustard,  63,  98,  436,  554 
Mutisiaceae,  512 
Mycelium,  235 
Mycetales,  337 
Mycoderma,  212 
Mycoporum,  310 
Myoporiueae,  498 
Myosotis,  502 
Myrica,  487,  564 
Myricaceze,  487,  564 
Myristica,  494 
Myristicaceae,  494 
Myrrb,  540 
Myrsinaceae,  506 
Myrsiphyllum,  460 
Myrtacea?,  425,  523,  565 
Myrtales,  522 
Myrtle  Family,  523 
Myrtle  (Trailing),  504 
Myrtle  Tree,  524 
Myrtus,  524 
Myxomycetes,  6,  10,  11.  15,  21, 


44,  59,  60, 170,  178.  207,  336,  340 

Naiadace*,  128,  466,  473 

Naiads,  128 

Naias,  14 

Naked  flowers,  431 

Narcissales,  467 

Narcissus,  61.  468 


Nasturtium,  543,554 
Navicula,  230 
I  Naviculese,  230 
Neck -cells,  402 
Nectandria,  494 
Nectar,  421 

Negative  Heliotropism,  193 
Negundo,  536 
Nelumbium,  131,  558 
Nemaliacefe,  339 
Nemaliou,  274,  277 
Nemophila,  503 
Neottieae,  470 
Nepentbaceae,  482 
Nepentbales,  482 
Nepentbes,  182,  482,  557 
Nepbelium,  537 
Nepbroma,  309 
Nereocystis,  268 
Nerium,  504 
Nettle,  11,  491 
Nettle  Family,  490 
Neutral  Flowers,  431 
Nicotiana,  502 
Nicotine,  182 
Nigella,  564 

Nigbt-Blooining  Cereus,  520 
Nigbtsbade  Family,  500 
Nipaceae,  463 
Nitella,  17,  200,  333 
Nitellege,  333 
Nitrates,  176,  180 
Nitrogen,  175,  180 
Nitzscbia,  231 

Nocturnal  positions  of  leaves,  199 
Norfolk  Island  Pine,  413 
Normandina,  310 
Norway  Spruce,  412 
Nostoc,  37,  206,  217 
Nostocacea;,  55,  216,  305,  306,  338 
Notelaea,  505 
Nucleoli,  16 
Nucleus,  16,  206 
Number  of  Species,  566 
Number  of  Stomata,  102,  103 
Nuphar,  131 
Nut,  436 
Nutation,  199 
Nutgalls,  479 
Nutlets,  436 
Nutmeg,  494 
Nutmeg  Family,  494 
Nut  oils,  482 
Nut  Pine,  413 


GENERAL  INDEX. 


507 


Nutrition  of  Parasites,  182 
Nutrition  of  Protoplasm,  180 
Nutrition  of  Saprophytes,  182 
Nux  Vomica,  503 
Nyctaginaceae,  497 
Nymphaja,  131,558 
Nympbceacen!,  128,  425,  557 
Nyssa,  519 

Oak,  64,  147,  172,  284,  421,  436, 

479 

Oak  Family,  477 
Oat,  56,  58,  59,  166,  316,  318,  322, 

323,  455 

Oblong  Leaves,  146 
Ochnaceae,  540 
Ochroma,  547 
Octandrous,  432 
(Edogoniacese,  269,  271,  339 
(Edogoniese,  246,  269,  336,  337 
(Edogonium,  10,  22,  42,  51,  250 
(Enothera,  11,  98,  418,  522 
Oidium,  284 
Oil,  62, 129 
Oil-cake,  544 
Oil  of  Caraway,  63 
Oil  of  Juniper,  411 
Oil  of  Lavender,  497 
Oil  of  Lemons,  63 
Oil  of  Peppermint,  497 
Oil  of  Rhodium,  502 
Oil  of  Thyme.  63 
Oil  of  Turpentine,  63 
Oily  Matter,  171),  181 
Okra,  547 
Olacales,  539 
Olacinese,  540 
Oldfieldia,  485 
Olea,  102,  505 
Oleacea?,  504,  565 
Oleander,  94,  504 
Olearia,  516 
Oleaster,  492 
Olibanum,  540 
Oligomeris,  552 
Olive,  505 
Olive  Family,  504 
Olive  Oil,  62,  505 
Omphalaria,  306,  309 
Onagraceae,  61,  522 
Onion,  61,  63.  77,  93,  199,  323,  458 
Onobrychus,  532 
Onygeneae,  338 
Onygenaceae,  339 


Oogonium,  243,  267 
Oospore,  46,  56,  243,  268 
Oosporea?,  205,  243,  269,  335,  337, 

339,  568,  569,  570 
Oospbere,  45,  243,  267 
Opegrapha.  310 
Opegraphei,  310 
Open  Bundle,  121,  443 
Opening  of  Flowers,  199 
Operculum,  355,  360 
Ophioglossacese,  371,  372,  379,  384, 

389 

Ophioglossum,  80,  380,  381 
Ophrydeae,  470 
Opium,  78,  556 
Opium  Poppy,  182,  556 
Opposite  Leaves,  149 
Optimum  Light,  191 
Optimum  Temperature,  184 
Opuntia,  150,  520 
Orange,  130,  132,  541 
Orang    Lily,  460 
Orchard  Grass,  455 
Orchidales,  468 
Orchidaceaa,  469 
Orchids,  137,  433,  469 
Orchil,  308 
Orchis,  470 
Ordeal  Poison,  504 
Organic  Acids,  180 
Organic  Compounds  as  Food,  176, 

178 

Organogeny  of  the  Flower,  426 
Orobanchaceae,  500 
Orobanche,  56 
Ornithogalum,  461 
Orthosti  clues,  149 
Oryza,  455 
Osage  Orange,  490 
Oscillatoria,  37,  67,  217 
Oscillatoriaceae,  217,  338 
Oscillatoriae,  53,  55 
Osmunda,  81,  377 
Osmundaceae,  377 
Ostrya,  72,  477 
Ourari,  503 
Ovary,  391,  417,  418 
Ovules,  136,  137,  390,  402,  419 
Oxalic  Acid,  64,  180,  182 
Oxalis,  197,  435,  542 
Ox  Eye  Daisy,  514 
Oxidation  in  Metastasis,  179 
Oxidized  Essences,  63 
Oxygen,  175 


598 


GENERAL   L\DHX. 


Pffionia,  426,  564 

Palisade  Tissue,  156 

Paliurus,  565 

Palm,  410,  44:},  463,  473 

Piilmacese.  425,  463 

Palma  Clirista,  484 

Palmales,  402 

Pal mately  compound  Leaves,  148 

Palmately-lobed  Leaves.  147 

Palmellaceae,  51,  218,  306,  339,  340 

Palmetto,  465 

Palm  Family,  463 

Palm  Oil,  62,  464 

Palm  Wine,  464 

Palmyra  Palm,  465 

Panama  Hats,  462 

Pandanaceze,  462,  473 

Pandanus,  462 

Pandorina,  10,  221,  242,  244,  336 

Panicle,  429 

Panicled  Heads,  429 

Panicled  Spikes,  429 

Panicum,  98 

Pannaria,  309 

Pannariei,  309 

Pansy,  551 

Papaver,  556 

Papaveracese,  77,  119,  556 

Papaw,  522,  561 

Papayaceaj(  —  Passitioracefle),  119, 

523 

Paper  Mulberry,  490 
Papilionacese,  531 
Pappus,  512 
Papyrus,  457 
Paraguay  Tea,  540 
Paraphyses,  288,  292,  353 
Parasite,  53,  176, 178,  182,190,  192, 

250,  270,  41  i 
Parasites,  Roots  of,  137 
Parastichies,  151 
Paratonic  Movement?,  196 
Parenchyma,  l,s.  69,  90,  106,    119, 

124,343,  351,  303,392 
Parietales,  551 
Parietal  Placenta,  4:31 
Parietaria,  150 

Pannelia,  296,  ^98,  301,  306,  309 
Parmeliacei,  308 
Parmeliei,309 
Paronycliieae,  494 
Parsnip,  166,  187,  428,  519 
Partridge  Berry,  517 
Passiflora,  522 


Passifloracese,  522 
1  Passi Morales,  520 
Passion  Flower  Family,  522 
Pasteur's  Solution,  214 
Pastinaca,  519 
Pasture  Thistle,  514 
Paullinia,  537 
Paulownia,  500 
Pea,  56,  58.  59,  149,  187,  188,  284, 

436,  531 

Peach,  62, 435,  530 
Peanut,  532 
Pear,  527 
Peat  Mosses,  357 
Pecan  Nut,  482 
Pectin,  63 
Pedaliaceae,  499 
Pediastrum,  65,224 
Pelargonium,  543 
Peltigera,  306,  309 
Peltigerei,  309 
Penseaceae,  484 

Penicillium,  215,  238,  285,  286,  289 
Pennyroyal,  497 
Pentacafpellary,  433 
Pentacyclic,  430 
Pentamerous,  430 
Pentandrous,  432 
Pentapetalous,  432 
Pentasepalous.  432 
Pentstemon,  500 
Peony,  58,  564 
Peperomia.  483 
Pepo,  436 
Pepper,  483,  561 
Pepper  Family,  483 
Pepper  Grass,  554 
Peppermint,  497 
Peppers,  501 
Pepperworts,  372,  381 
Peppridge.  519 
Pi-ritmth.  349,  418,  431 
Periblem,  162 

Pericamhium,  110,  1 1 1,  162,  164 
Pericarp,  273.  275,  40(1,  4:55 
Periclia?tium.  342.  346 
Peridium,  312,  324 
Perigynous.  434 
Peril  fa,  498 
Periplora,  503 
Perispcrra,  425 
PerisporiacesR,  273,  278 
Peristome,  360 

ithrcium  (pi.— a.),  281,  2S<»,  •>!>: 


UKXKRAL   IXDEX. 


Periwinkle,  33,  504 
Permanent  Tissues,  86,  144 
Peronospora,  259,  264 
Peronosporacwe,  339 
Peronosporea;,   40,    258,    2(59,   317, 

337,  340 
Persea,  494 
Persimmon,  506 
Personates,  498 
Pertusaria,  298,  309 
Peruvian  Bark,  64,  182,  517 
Petal,  417,  430 
Petalostemon,  532 
Petiole.  145,  369 
Petunia,  98,  502 
Peyssonnelia,  277 
Peziza,  270,  271,  280,  288,  289,291, 

297,  301,  323,  330 
Phacelia,  503 
Puacidium,295 

Phaeosporeae,  265,  208,  269,  337,  339 
Phallus,  324,  325 
Pham-roganiia,  204,  205,  389,  568, 

569,  570 
Phanerogams,  11,  40,  46,  56.  66,  72, 

74,  76,  82,  87,  90,  92,  100,  120, 

123,  137,  140,  101,  164,  205,  270, 

284,  310,  317,  389 
Phascacess,  355.  358 
Phascum,  358 

Phaseolus,  88,  475,  531,  532 
Pheasant's  Eye,  504 
Phellodendron,  542 
Phellogen,  120 
Philadelphia,  103,  526 
Philydrese,  457 
Phleum,  455 
Phloem,  118,  407 
Phlox,  503 
Phoenix,  465 
Phoradendron,  51,  477 
Phosphates,  176 
Phosphorus,  175 
Phrajrmulium,  314,  315 
Phycochromaceae,  340 
Phycocyanine,  216 
Phy corny ces,  241 
Phycomycetfs,  338 
Phycoxan thine,  216,  227 
Phyllactinia,  281,28:5 
Phyllocladus,  410 
Phyllocyanine,  52 
Phylloglossum,  382,  385 
Pli'yllome,  134,  130,  243,  271 


Phyllotaxis,  149 

Phylloxanthine,  52 

Physalis,  500 

Physarum,  210 

Physcia,  306,  309 

Physiological  Unit,  20 

Physocalymma,  523 

Pliysomycetes,  338 

Phytelephas,  463 

Phytelephasiete,  40-! 

Phytolacca,  497 

Phytolaccaceae,  497 

Picea,  151,409,411,412 

Pie  Plant,  497 

Pigeon  Pea,  532 

Pileorhiza,  159,374,  424 

Pileus,  328 

Pilohohis,  237,241 

Pilophorus,  309 

Pilularia,  381,  382 

Pimento,  523 

Pinang,  466 

Pinckneya,  517 

Pine,  94,  412 

Pineae,  411 

Pine-apple,  62,  471 

Pine-apple  Family,  4T1 

Pinguicula.  500 

Pinluen  Oil,  484 

Pink  Family,  549 

Pinnately-comp0und  Leaves,  1  18 

Pinnately  lobed  Leaves,  147 

Pinnate  Venation,  145 

Pinus,  34,  69,   85    102,  151.  395, 

397,409,  411,412,415 
Piper,  483,  561 
Piperaceae,  425,  483 
Piperales,  483 
Pipsissewa,  510 
Piptocephalis,  238,  241 
Pirus,  72,  75,  85,  103,  527,  564 
Pistacia,  535 
Pistachia  Nut,  535 
Pistil,  419,  433 
Pistillate  Flowers,  431 
Pisum,  102,  531 
Pitch,  412 
Pitchers,  13(5 
Pitcher  Plant,  556,  557 
Pith,  124,  128,  200,  201,  408 
Pits  in  Cell  walls,  24 
Pitted  Vessels,  84,  113.  303 
Pittosporaceae,  551 
Pittosporum,  551 


600 


GENERAL   INDEX. 


Placenta,  419,  433 

Placodium,  309 

Plagianthus,  547 

Plane  Tree,  487 

Plane  Tree  Family,  487 

Platanacese,  487,  565 

Platanus,  102,  487,  564,  565 

Platygrapha,  310 

Platyzoraa.  376 

Plautaginaceae,  507 

Plantago,  106,  507 

Plantain,  106,  428,  472,  507 

Plantain  Family,  507 

Plant  Body,  133 

Plant  Cell,  15 

Plant  Food,  175 

Plasmodiuin  (pi.— a)  (5,  207 

Plectospora,  302 

Plerome,  161 

Pleurocarpae,  359,  360 

Pleurocarpus,  235 

Pleurosigma,  230 

Plum,  62,  146,  292,  426,  530 

Plumbaginaceae,  507 

Plumbago,  508 

Plumule,  186,  386,  404,  474 

Phycoerythrine,  276 

Poa,  279  455 

Podisoraa,  (see  Gymnosporangium) 

Podocarpus,  409,  410 

Podogonium,  565 

Podopbyllum,  559 

Podosphaera,  271,  281,  283 

Pogonatum,  359 

Poison  Hemlock,  520 

Poison  Ivy,  165,  516,  535 

Poison  Oak,  535 

Poison  Sumach,  535 

Poke-berries,  173 

Poke -weed,  497 

Pole  Bean,  188,  531 

Polernoniaceae,  503 

Polemoniales,  500 

Polemonium.  503 

Polianthes,  461 

Pollen,  34,  46,  136,  389,  417 

Pollen-sac,  394.  418 

Pollen  Tube,  47,  391 

Pollination,  420,  431 

Pollinia,  503 

Polyactis,  288 

Polyandrous,  432 

Polyanthus,  468 

Polyarthrodactylse,  334 


Polycarpellary,  433 
Polygala,  551 
Poly  ga  I  ace*.  550 
Polygalales,  550 
Poljgamoufl  Flowers,  431 
Polygonaceae,  64,  496 
Polygon  uin.  32:5,  496,  497 
Polygynoecial  Fruits,  437 
Polyhedral  Cell,  19 
Polyides,  277 
Polypetalefi,  476.  518 
Polypetalous,  431,  432 
Polypodiaceae,  377 
Polypodium,  109,  377 
Polypori,  241 
Polyporites,  331 
Polyporus,  328,  330,  331 
Polysepalous,  431,  432 
Polysipbonia,  277 
Polysiphonidea,  278 
Polysymmetrical  Flowers,  430 
Polytrichum,  150,  352,  359,  360 
Pome,  436 
Ponieae,  527 
Pomegranate,  523 
Pondweeds,  466 
Pontederaceae,  457 
Pontederales,  457 
Porcupine  Grass,  157 
Portlandia,  518 
Poplar,  428 
Poppy, 556 
Poppy  Family,  556 
Populus,  150.  487,  564,  565 
Populus,  102,  143 
Portulaca,  197,  264,  549 
Portulacacese,  549 
Potamales,  466 
Potamogeton,  131,  186 
Potash  Salts,  176 
Potassium,  175 

Potato,  56,  58,  166,  181, 187,  500 
Potato  Fungus,  264 
Potentilla,  264 
Potentilleas,  528 
Prickles,  137 
Prickly  Ash,  127,  542 
Prickly  Pear,  520 
Pride  of  India  Tree,  540 
Primary  Bundle,  121 
Primary  Cell-wall,  35,  68 
Primary  Cortex,  408 
Primary  Meristem,  86,  88,  89,  106 
121,  138,  144, 161 


GENERAL   INDEX. 


C01 


Primary  Root,  159 

Primary  Stem,  140 

Primary  Wood,  406,  408 

Primine,  419 

Primordial  Utricle,  5 

Primrose,  94,  98,  104,  50(5 

Primrose  Family,  506 

Primula,  94,  98,  104,  506 

Primulacea?,  506 

Primulales,  506 

Prince's  Pine,  510 

Principal  Tissues,  69 

Pringsbeimia,  250 

Prismatic  Cell,  19 

Privet,  505 

Procambium,  121 

Pro-embryo,  332,  341,  391,  423 

Progressive  Division,  49 

Promycelium,  314,  320 

Prosenchyma,  18 

Protamceba,  15 

Protea,  491 

Proteaceae,  491 

Proterandrous,  434 

Proterogynous,  434 

Protballium  (pi.— a),  361.  389,  403, 

418,  420 
Protococcus,  36,   37,   65,  185,219, 

221,  307 

Protodermeifi,  210 
Protomeristem,  86 
Protomycetes,  338 
Protomyxa,  15,  207 
Protonema  (pi.—  ata),  341,  356 
Protopliyta,  205,  206.  306,  335.  336, 

568,  569,  570 
Protophytes,  206 
Protoplasm,  1,  94,  166 
Protoplasm-Sac,  5,  15 
Prototaxis,  415 
Prototype,  134 
Protozoa,  207 
Pruneae,  530 

Prunus,  102,  103,  530,  564 
Pseudolarix,  409 
Pseudopodium  (pi. — a).  8,  355 
Pseudo-Raphidieaj,  230 
Pseudospores,  313 
Pseudotsuga,  411 
Psidium,  523 
Psilotum,  382,  385 
Ptseroxylon,  535 
Ptelea,  542 


Pteridophyta,  205,    335,   361,  368, 

369,  370 
Pteridophytes,  10,  40,  59,  72,  74, 

80,  82.  86,  90,  92,  106,  121,  137, 

140,  161,  164,  361,  389,  418,  437 
Pteris,  72,  80,  81,  85.  88, 107,  110, 

111,  309,  377 
Pterocarpus,  532 
Pterocarya,  565 
Pterophyllum,  416 
Puccinia,  39,  315,  816 
Puff-Ball,  324,  326 
Pulque,  468 
Pulse  Family,  531 
Pulu,  378 
Pulvinus,  197 
Pumpkin,    29,   98,    187,  200,  436, 

437,  522 
Punica,  523 
Punctum  Vegetationis,  87, 138, 140, 

144,  149,  424,  444 
Purslane,  93,  549 
Pycnidia,  281,  293,  299 
Pycnidiospores,  281,  294 
Pyrenastrum,  310 
Pyrenomycetes,  289,  295,  299,  338, 

339 

Pyrenula,  310 
Pyrolineje,  508,  510 
Pyxine,  309 
Pyxis,  436 

Quadrilocular,  433 
Quandang  Nut,  476 
Quassia,  540 
Quercinese,  478 
Quercitron,  480 
Quercitron  Oak,  480 
Quercus,  17,  85,  150,  479,  564 
Quernales,  477 
Quillaja,  529 
Quillaja  Bark,  529 
Quillajeae,  529 
Quill  worts,  387 
Quince,  35,  149,  527 
Quinia,  64,  5*17 
Quinic  Acid,  64,  182 
Quinine,  517 

Raceme,  428 

Radial  Bundle,  113,  362,  392 
Radiately-compound  Leaves,  148 
Radiately-lobed  Leaves,  147 


602 


GENERAL   INDEX. 


Radiate  Venation,  145 

Radicle,  404,  474 

Radish,  98.  554 

Raiflesia,  270,  482 

Rafflesiaceae,  270,482 

Ragweed,  515 

Rainfall,  172 

Ranmlina,  307,  308 

Ramie,  491    ' 

Ramose  Cell,  19 

Ranales,  466,  557 

Ranunculaceae,  284,  328,  425,  437, 

562 

Ranunculus,  14,  117,  564 
Rapate«e,  457 
Rape,  554 
Raphanus,  150,  554 
Rapl.idea,  59,  61 
Raphidiese,  230 
Raspberries,  64,  437,  529 
Rattan,  465 
Rays  of   Different    Refrangibility, 

Receptacle,  291,  349,  376,  381,  417 

Red  Bay,  494 

Red  Clover,  166 

Red  Currant,  526 

Red -Hot  Poker  Plant,  461 

Red  Lily,  460 

Red  Oak,  480 

Red  Pine,  412 

Red  Rust,  39,  316 

Red  Sandal  wood,  532 

Red  Seaweeds,  53,  273 

Red-Snow  Plant,  185 

Red  Top,  455 

Reduced  Bundles,  121 

Redwood,  411 

Regular  Flowers,  430 

Reindeer  Moss,  309 

Rejuvenescence.  42,  47,  2^9,  247 

Relations   of  Caulome,   Phyllome 

etc. ,  135,  138 

Relations  to  External  Agents,  184 
Reproductive  Cells,  47 
Reseda,  552 
Resedaceae,  552 
Reserve  MaterisO,  181,  187 
Reservoirs  for  Secretions,  129 
Residual  Products,  61 
Resin,  62,  63,  129 
Resin  Canals,  132 
Resinous  Substances,  96 
Restiacese,  457 


Restiales.  457 
Restio,  150 

Resting  Spore,  218,  220 
Resting  Stage,  20S,  212 
iesults  of  Metastasis,  183 
Resurrection  Plant,  555 
ieticularia,  211 
Reticulated  Thickening  28 
ieticulated  Vessels,  83,  111 
Jetinospora,  411 
ihabdonema,  231 
ihodanthe,  515 
Rhodoreas  511 
ilhamnaceaei  538.  565 
Rhamnus,  539,  565 
Rheum,  71   496 
Rhexia,  523 
Rhizocarpeas   370,   371,   372,    378 

381,  389 
Rhizocarps,  381 
Rhizoids,  343.  351,  361 
Rhizophora,  524 
Rhizophoraceae,  524 
Rhizosolenia,  231 
Rhododendron,  510 
Rhodomelacese,  339 
Rhodomelese,  277,  278 
RhodospermeiB.  337 
Rhodymenia,  277 
Rhodvmenieae,  277 
Rhoicosphenia,  230 
Rhubarb,  61,  64,  496 
Rhus,  150,  165,535,565 
Rhytisma,  295 
Ribes,  102,  526 
Riccia,  346,  348,  349 
Ricciac.-ae,  350,  361 
Rice,  56,  59,  455 
Rice  Paper,  519 
Richardia,  462 
Ricinus,  59,  &5,  115    118    120,  475 

484 

Riga  Fir,  412 
Right,  to  the,  199 
Ring,  328.  325 
Ringed  Vessels,  83,  113 
Ringless  Ferns,  372,  378 
Rings,  28 
Rinodina,  309 
Ripening  of  Seeds,  58 
Kivulariaceae,  217,  338 
Rivularia,  206,  218 
Robinia,  17,  61,  150,  532 
Roccella,  308 


GENERAL  INDEX. 


6o:> 


Rochea,  106 

Rocket,  554 

Rock-weeds,  269 

Root,  134,  137,  159,  187,  190,  191. 

243,  265,  362,  374,  404,  424 
Root-cap,  159,  161,  374,  404 
RooUiairs,   19,   95,   1"7,  101,    342 

351,  361,  367 
Root-pressure,  173 
Roots  as  Storehouses,  1(55 
Root-stock,  136 
Rosa,  527 

Rosacese,  64.  150,  425,  5:27,  5(55 
Rosales,  524 
Roseje,  527 
Rose  Apple,  523 
Rose  Family,  527 
Rosemary,  497 
Rose  Mallow,  547 
Rose  of  Jericho,  555 
Roses,  283,  437,  527 
Rosette,  402 
Rosewood,  505,  532 
Rosin,  63,  412 
Rosmarinus,  497 
Rotation  of  Organs,  199 
Rotation  of  Protoplasm,  14 
RubwB,  529 
Rubia,  518 
Rubiacese,  516 
Rubiales,  51(5 
Rubus,  529 
Rudbeckia,  151 
Rudiments  of  Floral  Organs,  42(3, 

431 

Rue,  132.  542 
Rue  Family,  541 
Rumex,  71,497 
Runners,  135,  193 
Ruscus,  461 
Rushes,  457 
Russia  Leather,  487 
Rust,  316 
Ruta,  132,  542 
Rutacese,  541 
llutese,  542 
Rye,  94, 166,  289,  294,  295,  455 

Sabal,  465 
Sabiacese,  535 

Saccharomyces,  17,  39,  65,  214 
Saccharomycetes,  336,  340 
Saccharum,  455 
Sack  Tree,  490 


Safflower,  513 
Saffron,  468 
Sage,  498 
Sage  Brush,  514 
Sagedia,  310 
Sagittaria,  131,  467 
Sago,  410 
Sago  Palms,  466 
Saguerus,  466 
Sagus,  466 
Salep,  470 

Salicacese,  425,  486,  565 
Salisburia,  410 
Salix,  480,  564,  565 
Salsify,  513 
Salvadoraceae,  504 
Salvia,  498 
Salvinia,  381,  382 
Salviniaceee,  382 
Samara,  436 
Sambucus,  106,  518 
Samydacete,  522 
Sanguinaria,  556 
Sandalwood  Tree,  476 
Sand-box  Tree,  485 
Sanfoin,  532 
Santalaceas,  476 
Santalales,  476 
Sanialum,  476 
Santa  Maria  Wood,  549 
Sap,  62,  174 
Sapindaceae,  535,  565 
j  Sapindales,  534 
Sapindeae,  536 
Sapindus,  565 
Sapodilla  Plum,  506 
Saponaria,  550 
Saponin,  461 
Sapotaceas,  506,  564 
Saprolegniaceaj,  39,   56,   254,  263, 

269,  337,  339,  340 
Saprolegniae,  11 
Saprophyte,  53,  176,  178,  182,  190, 

221,  250,  270,  281,  286,  323 
Sarcodes,  511 


Sargassum,  268 
Sarracenia,  182,  556 
Sarraceniaceae,  556 
SarsaparSlla,  459 
Salt,  diffusion  of,  175 
Sassafras,  494,  564 
Sassafras  Bark,  494 
Satin- Wood,  540 


604 


GENERAL  INDEX. 


Saunders,  532 

Saururus,  483 

Saw  Palmetto,  465 

Saxifraga,  106, 193,  194,  526 

Saxifragacese,  526 

Saxifrage  Family,  526 

Scabiosa,  516 

Scalariform  Thickening,  28 

Scalariform  Vessels,  84,  107,  363 

Scales,  90,  136,  137,  155 

Scarnmony,  502 

Scarlet  Bean,  187 

Scarlet  Oak,  480 

Scattered  Leaves,  149 

Schalen,  34 

Schizomycetes,  178,  211.  336,  338 

Schinus,  535 

Schizaea,  377 

Schizseacese,  377 

Schizocarpic  Fruits,  436 

Schizosporeae,  338 

Scliizoxylon,  415 

Schizynemia,  277 

Schulze's  Maceration,  35 

Sciadopytis,  411 

Scilla,  459 

Scirpus,  150,  318 

Scitaminese,  471 

Sclerenchyma,  71,  89, 112,  124,  343, 

351.  363,  392 
Sclerotium,  290,  294 
Sclerotium  Stage,  208 
Scolecite,  288 
Scolopendrium,  377 
Scorpioid  Cyme,  429 
Scorpioid  Monopodium,  140 
Scorpioid    Syinpodial    Dichotomy, 

140 

Scotch  Fir,  412 
Scotch  Pine,  412 
Scouring  Rushes,  35 
Screw  Pine,  462 
Scrophulariaceae,  500 
Scutellum,  451 
Scytonema,  218 
Scytonemacese,  218,  338 
Secale,  103.  455 
Secondary  Cell-wall,  68 
Secondary  Cortex,  408 
Secondary  Embryo-sacs,  402 
Secondary  Leaves,  147 
Secondary  Spirals,  151 
Secondary  Spores,  320 
Secondary  Sporidia,  320 


Secondary  Wood,  408 

Secretion  Reservoirs,  128 

Section-Cutter,  122,  165 

Sections  of  Leaf-buds,  154 

Secundine,  419 

Sedges,  318,  421 

Sedge  Family,  4o7 

Sedum,  150,  526 

Seed,  167,  181,  188.  391,  404,  426, 

437 

Segestria,  310 
Selaginella,  111,  112,  123,  382,  386, 

387 
Selaginell*,  121,  383,  385,  387,  391, 

397 

Sempervivum,  526 
Senecio,  514 
Senecionidese,  514 
Senna,  533 

Sensitive  Plant,  197,  198,  534 
Sepal,  417,  430 
Septicidal  Dehiscence,  435 
Sequoia,  81,  411,415,416 
Serrate  Leaf,  147 
Service-Berries,  527 
Sesamum,  499 
Sesbania,  532 
Seta,  342,  355 
Setaria,  323 
Seville  Orange,  541 
Sexual  Act,  206 
Sexual  Generation,  341,  361 
Sexual  Organs,  206 
Shaddock,  541 
Shallot,  458 
Sheep  Laurel,  510 
Shell-bark  Hickory,  482 
Shells,  34 

Shepherdia,  98,  492 
Shepherd's  Purse,  554 
Shields,  331 
Shower  of  Lichens,  309 
Showy  Lily,  460 
Sida,  547 
Sieve  Cells,  28 

Sieve  Tissue,  79,  106,  363,  392 
Sigillaria,  385 
Sigillarieae,  885 
Silene,  550 
Silenese,  318 
Silicates,  176 
Silicon,  175 
Silique,  436 
Silk  Oak,  491 


GENERAL  INDEX. 


605 


Silk  Tree,  547 

Silphium,    70,    71,  103,    132,    156, 

159,  515 

Silver-Bell  Tree,  505 
Silver  Fir,  412 
Silver  Poplar,  173 
Silver  Tree,  491 
Simaruba,  540 
Simaruba  Bark,  540 
Siuiarubaceae,  540 
Simple  Leaf,  147 
Simple  Pistil,  433 
Simultaneous  Division,  49 
Single  Cells,  65 
Siphonacete,  339 
Siphoneae,  340 
Sirurella,  231 
Sirurellese,  231 
Sisymbrium,  98 
Size  of  Cells,  16 
Size  of  Leaves,  146 
Skimmia,  542 
Skunk  Cabbage,  462 
Sleep  of  Plants,  198 
Slime  Moulds,  6,  170,  188,  207 
Slippery  Elm,  488 
Sloan  ea,  545 
Slough  Grass,  455 
Smart  weed,  497 
Smilacina,  428 
Smilax,  459,  460 
Smut,  318,  323 
Snake  wood,  490 
Snapdragon,  500 
Sneeze  wood  Tree,  535 
Snowball,  518 
Snow  berries,  518 
Snowdrop,  468 
Snowdrop  Tree,  505 
Snow  flake,  468 
Snow  Plant,  511 
Soap  Bark,  529 
Soda  Salts,  176 
Sodium,  175 
Soft  Bast,  116 
Solanacese,  71,  425,  500 
Solan  urn,  11,  102,  500 
Solidago,  516 

S  >litary  Axillary  Inflorescence,  428 
S)litary  Spores,  319 
Solitary    Terminal     Inflorescence, 

429 

Sollya,  551 
Solorina,  309 


Solutions,  174 

Sonneratia,  523 

Sophora,  532 

Soredia,  305 

Sorghum,  457 

Sorisporium,  319 

Sorrel,  497,  542 

Sorosis,  437 

Sorus  (pi.— sori),  313,  374 

Sour  Gum,  519 

Sour  Sop,  561 

Soy,  532 

Spadix,  428 

Spanish  Bayonet,  461 

Spanish  Chestnut,  478 

Spanish  Needles,  515 

Sparganium,  462 

Speerschneidera,  309 

Spergula,  550 

Spermagonium    (pi.— a),  293,  298, 

312 
Spermatium(pl.— a),  293,  299,  312, 

315, 323,  330 
Spermatozoids,    45,    46,   243,    267, 

271,  330,  332,341,  362 
Sperm  Cells,  341,  362. 
Sphacelariaceae,  339 
Sphacelia,  289 
Sphajria,  292, 294,  295 
Sphaeriacese,  339 
Sphaerobacteria,  213 
Sphaerococcaceae,  339 
Sphasrococcites,  278 
Sphaerococcoidese,  277,  278 
Sphaerophorei,  310 
Sphaerophorus,  301,  310 
Sphseroplea,  245,  247 
Sphaeropleacese,  339 
Sphaerotheca,  281,283 
Sphagnaceae,  352,  355, 356,  357 
Sphagnum,  351,  357,  358 
Sphenophyllum,  368 
Spheroidal  cell,  19 
Spicules,  324 
Spiderwort,  457 
Spike,  395,  428 
Spinach,  495 
Spinacia,  495 
Spines,  136 
Spiraea,  529 
Spiraeeae,  529 
Spirals,  28 

Spiral  Vessels,  82,  85, 108,  363 
Spiranthes,  470 


coo 


GENERAL   INDEX. 


Spirillum,  213 

Spirobacteria,  213 

Spirochaete,  213 

Soirogyra,  11,  22,  37,  44,  51,  57,  67, 

232,  234, 241 
Splachnum,  359 
Spongiocarpese,  277 
Sporangium  (pi.— a),  137,  210,  236, 

325,  366,  374,  378 
Spontaneous  Movements,  196 
Spore-case,  342,  355 
Spores,  137, 170,  188, 209.  236,  342, 

361 

Spore-sac,  360 
Sporidia,  290,  314,  317,  320 
Sporocarp,  270,  273,  274.323,  327 
Sporochnaceae,  339 
Sporogonium(pl.— a;,  342,  348,  354 
Spumaria,  210 
Spurious  Tissues.  65 
Spurge  Family,  484 
Spyridia,  277 
Squamarieae,  277 
Squash,  29,  522 
Squill,  459 
Stachys,  441 
Stack  housiese,  539 
Stamen.  136,  197, 199,  394,  418, 430 
Staminate  Flowers,  431 
Stapelia,  503 
Stapliylea,  535 
Staphyleae,  535 
Star  Apple,  506 

Starch,  53.  78,  165, 179,  181,187 
Starch  Cellulose,  55.  56 
Star  of  Bethlehem,  461 
Stauroueis,  230 
Staurothele,  310 
Stellate  Cell,  19 
Stem,  135, 140,  181,  187,  265 
Stemonitis,  9.  210 
Stephanodiscus,  231 
Stephanopyxis,  231 
Stephanotis,  503 
Sterculiaceae,  545 
Stereum,  328,  330 
Sterigma  (pi.— ata),  282,  299,  312, 

329 

Sterocaulon,  309 
Sticta,  296,  301.  309 
Stigeoclonium,  42 
Stigma,  197,  419 
Stinging  Nettles,  491 
Stink-Horn,  325 


Stipa,  103,  157 

Stipules.  148 

Stoffwechsel,  180 

Stoma(pl.  stomata),  39,  90,  91,  92, 
99,  155,  170,  185,  191,  312.  84?,. 
350,  352,  359,  362,  367.  392.  437 

Stomata,  Number  of,  102,  103 
|  Storing  of  Reserve  Material,  181 
I  Stratification  of  Cell-wall,  32,  93 
I  Strawberries,  62,  64,  434,  529 

Strawberry  Geranium,  526 
I  Strawberry  Tomato,  500 

Streaming  of  Protoplasm,  6 

Strelit/ia,  472 

Striatella,  231 

Striation  of  Cell-wall,  33 

Strigula,  310 

Strings  of  Protoplasm,  16 

Strobile,  437 

Strychnia,  182,  503 

Strychnos,  182,503 

Stuartia,  548 

Styles,  199 

Stylidiacea?,  512 

Stylidium,  512 

Stylospores,  39,  293,  315 

Styracaceae,  505 

Styrax,  505 

Sucrose,  62 
|  Sugar,  62,  165,  455 

Sugar  Beet,  62,  495 

Sugar  Cane,  62,  93,  495 

Sugar,  Diffusion  of,  175 

Sugar  Maple,  62,  174,  535 

Sugar  Pine,  412 

Sugary  Matter,  179 

Sulphates,  176,  180 

Sulphur,  175,  180 

Sulphuretted  Essences,  63 

Sumach,  64,  535 

Sumatra  Camphor,  547 

Summer  Buds,  141 

Sundew,  526 

Sundew  Family.  526 

Sunflower,  159,  171,  173,  188,  436, 
514 

Sunflower  Family.  512 

Supernumerary  Buds,  143 

Supernumerary  Stems,  143 

Supple  Jacks,  537 

Supporting  Tissue,  89 

Suppression  of  Floral  Organs,  431 

Suspended  Ovules,  433 

Suspension  of  Movements,  198 


GENERAL   INDEX. 


Suspensor,  385,  391,  404,  423 
Swarmspores,  36,   209,    222,    260, 

263,  273 

Sweet  Alyssum,  554 
Sweet  Bay,  562 
Sweet  Gum-Tree,  526 
Sweet  Oil,  505 
Sweet  Potato,  143,  165,  502 
Sweet  Sop,  :.(il 
Swietenia,  540 
Symmetry  of  Leaves,  146 
Sympetalous,  432 
Svmpodial    Cyinose    Monopodium, 

'140 

Syinpodial  Dichotomy,  140 
Symphoricarpus,  11,462,  518 
Synalissa,  309 
Synantherous,  433 
Syncarpous,  433 
Synedra,  231 
Syngenesious,  433 
Sycamore,  487 
Syconus,  437 
Syringa,  102,505 
Systems  of  Tissues,  89 
System  of  Orouud  Tissues,  123 

Tabellaria,  231 
Tabellarie*.  231 
Tabemaeinoiitaua,  504 
Tabular  Cell,  19 
Taccaceae,  468 
Taccades.  468 
Tagetes,  514 
Tallow  Tree,  485 
Tamarack,  412 
Tamarind,  64,  533 
Tamarind  us,  533 
Tamariscine*,  549 
Tamarisk,  549 
Tamarix,549 
Tanacetum.  514 
'1'anbark  Oak,  480 
Tanghin,  504 
Tanghinia,  504 
Taunic  Acid,  64,  182 
Tansy,  514 
Taraxacum,  62,  512 
Tares,  532 

Tartnric  Acid,  64,  182 
Tar,  412 
Tapioca,  484 
Taxine«,  400,  410 
Taxodiese,  411 


Taxodium,  409,  411 

Taxus,  102,  395,  399,  409,  410 

Tea,  182,548 

Teak,  48r>,  498 

Teasel,  516 

Tecoina,  499 

Tuctona,  498 

Tegmeu,  437 

Tela  Contexta,  66 

Teleutospores,  313 

Temperature,  169,  184,  198 

Tendril,  136,  200 

Teredo,  524 

Termes,  524 

Terminal  Growth  of  Cells,  22 

Ternstrcemiaceae.  548 

Terpsinoe,  231 

Tetracarpellary,  433 

Tetracyclic,  43~0 

Tetradyuamous,  432 

Tetramerous,  430 

Tetrandrous,  432 

Tetrauthera,  494,  565 

Tetraphis,  357 

Tetrapetalous,  432 

Tetrasepalous,  431 

Tetrasporeae,  339 

Tetraspores,  273 

Testa,  426,  437 

Testudinaria,  467 

Thallophyta,  203,  204,  205 

Thallophytes,  17,   18.    37,  56,   90, 

140,  145,  205,  264,  357 
Thallophytes,  Classification  of,  335 
Thallome,  134,  243 
Thallus,  342,  461 
Thamuochortus,  150 
Tbea,  548 
Theca,  355 

Tbeloscbistes,  307,  309 
Tbelotrema,  309 
Theobroma,  545 
Theobromine,  546 
Tbeories  as  to  Thickening  of  the 

Cell  wall,  30 
Tbespesia,  547 
Thickening  of  Cell  wall,  23 
Thistles,  99,  187,  513 
Tborn  Apple,  502 
Thorns,  136 
Thrift,  508 
Thunbergia,  499 
Thuya, 409,  411 
Thyme,  497 


608 


GENERAL  INDEX. 


Thymelseaceae,  492 

Thymus,  497 

Thyrsus,  429 

Tieute,  503 

Tiger  Lily,  460 

Tilia,  150,  545 

Tiliaceae,  545 

Tillandsia,  471 

Tilletia,  318,  323 

Tilopterideae,  339 

Timothy,  455 

Tipularia,  470 

Tissues,  65,  69,  343,  358,  362,  367, 

405 

Tissues  of  Angiosperms,  437 
Tissue  Systems,  89 
Tjettek,  503 
Tmesipteris,  382,  385 
Toadstools,  39 
Tobacco,  182,  184,  50'3 
Toddalieaj,  542 
Toddy  Palms,  466 
Todea,  377 
Tolypella,  333,  334 
Tomato,  98,  164,  500 
Torreya,  409,  410 
Torsion,  200 
Torus,  417 
Touch-Me-Not,  542 
Towel  Gourd,  522 
Tracheary  Tissue,  81, 10G,  363,  392 
Trachei'des,  84,  116,  407 
Trachylobium,  533 
Trachyinene,  520 

Tradescantia,  11,  12,  13,  61,  98,  457 
Tragopogon,  512 
Trailing  Arbutus,  510 
Trailing  Myrtle,  504 
Transitory  Rigidity,  198 
Transformation  of  Starch,  180 
Transpiration,  169,  185 
Transportation  of  Food,  176 
Transverse  Tension,  201 
Trapa,  164,  522 
Tree  Ferns,  146,  373,  377,  410 
Tree  Nettle,  491 
Tree  of  Heaven,  541 
Tremandrese,  551 
Tremella,  289 
Tremellaceae,  339 
Tremellini,  323,  330,  338 
Triadelphous,  432 
Triandrous,  432 
Tricarpellary,  433 


Trichia,  211 

Trichobasis,  316 

Trichogyne,  271,  286,  300 

Trichomanes,  376 

Trichome,  92,  95,  134, 137, 161,340, 

362,  392,  437 
Trichophore,  275 
Tricyclic,  430 
Trifolium,  103,  532 
Trigynous,  433 
Trilocular,  433 
Trimerous,  430 
Trimorphous,  435 
Tripetalous,  432 
Trisepalous,  431 
Triticum,  453 
Tritoma,  461 
Triurales,  467 
Triurideje,  467 
Trollius,  564 
Tropoeolum,  106,  543 
Truffle,  285 
Trypethelium,  310 
Tsuga,  33,  150,  409,  411 
Tuber,  136,  181,  190,  191,  285,  286 
Tuberaceae,  273,  285,  338  339 
Tuberose,  461 
Tubulina,  211 
Tulip,  93,  102,  461 
Tulipa,  461 
Tulipoinania,  461 
Tulip  Tree,  523,  562 
Tulip  Wood,  537 
Tumble  Weed,  496 
Tupelo,  519 
Turban  Lily,  460 
Turgidity  of  Cells,  167 
Turkey  Oak,  480 
Turk's  Cap  Lily,  460 
Turmeric,  472 
Turneraceae,  522 
Turnip,  166,  185,  554 
Turpentine,  63,  409,  412 
Turpentine  Canals,  130 
Twigs,  181 

Twining  of  Organs,  200 
Typha,  462 
Typhaceas,  462 

Ullucus,  495 
Ulmaceffi,  488 
Ulmus,  150,  488 
Ulva,  225 
Ulvacese,  67 


GENERAL  INDEX. 


609 


Umbel,  428 
Umbellales,  418 
Umbelliferae,  129,  436,  519 
Umbellularia,  494 
Umbilicaria,  298,  301,  309 
TJmbilicariei,  309 
Umbrella  Tree,  562 
Uncinula,  281,  283 
Unicorn  Plant,  499 
Unilocular.  433 
Uniparous  Cyme,  429 
Unisexual  Flowers,  431 
Upaa  Tieute,  503 
Upas  Tree,  490 
Urari,  503 
Urceolaria,  298,  309 
Uredinaceae,  339 
Uredineie.  310,  317,  320,  337 
Uredo,  316 
Uredospore,  312 
Urocystis,  320,  323 
Urotnyces,  315 
Uropyxis,  315 
Urtica,  11,  61,  491 
Urticaceae,  61,  77,  490 
Urticales,  488 
Usnea,  296,301,  306,308 
Usneei,  308 
Ustilaginaceae,  339 
Ustilagineae,  317,  337 
Ustilago,  318,323 
Utricle,  436 
Utricularia,  182,  500 

Vacciuiese,  508,  511 
Vaccinium,  511,  565 
Vacuoles,  5,51,  167,  189,  197 
Valerian,  516 
Valeriana,  516 
Valerianaceae,  516 
Vallisneria,  14,  186,  473 
Valsa,  294 

Valves  of  Diatoms,  227 
Vandeaj,  470 
Vanilla,  470 
Vascular  Bundle,  106 
Vascular  Cryptogams,  361 
Vascular  Plants,  205 
Vascular  Tissues,  119 
Vaucheria,  10,  45,  250,  254 
Vauclieriacese,  254,  269 
Vegetable  Alkaloids,  64 
Vegetable  Jelly,  63 
Vegetable  Mucilage,  63 


Vegetative  Cells,  49 

Vegetative  Cone,  87 

Vegetative  Point,  87 

Veil,  328 

Veins  of  Leaves,  145 

Venation,  145,  475 

Venice  Turpentine,  412 

Ventral  Suture,  433 

Venus'  Fly-Trap,  526 

Veratrum,  459 

Verbascum,  150,  500 

Verbena,  98,  284,  498 

Verbeuaceae,  498 

Vermiform  Body,  288 

Vernonia,  516 

Vernoniaceae.  516 

Veronica,  500 

Verrucaria,  306,  310 

Verrucariaceae,  310 

Verrucariei,  310 

Versatile  Antliers,  433 

Vervain  Family,  498 

Vessel-cells,  17 

Vessels,  66,  167 

Vetch,  58,  59,  149,  533 

Vibrio,  213 

Viburnum,  17,  127,  518,  565 

Vicia,  14,  38.  150.  531,  532 

Victoria,  146,  558 

Victoria  Lily,  558 

Vinca,  33, 102,  428,  504 

Vine,  61,  171,  174,  193,  537 

Viola,  421,  436,  551 

Violaceae,  425,  551 

Violet  Family,  551 

Violets,  551 

Virginia  Creeper,  61,  155,  165,  193, 

538 

Virgin's  Bower,  284,  564 
Viscum,  477 
Vitex,  498 

Vitis,  81,  85.  103, 150,  174,  537 
Vochysia,  550 
Vochysiaceae,  550 
Volvocaceae,  339 
Volvocinese,  221 
Volvox,  223,  243,  268,  269,  337 
Vulcanized  Rubber,  485 

Waahoo.  539 
Wagen-boom,  491 
Waking  of  Plants,  198 
Walking-sticks,  2(59 
Wallflower,  554 


610 


GENERAL  INDEX. 


Walnut,  421,  480 

Walnut  Family,  480 

Washingtonia,  4C5 

Water  as  Plane  Food,  176 

Water  Chestnut,  522 

Water  Chinquepiu,  558 

Water  Cress,  554 

Water  Hemlock,  520 

Water  in  Cell-walls,  167 

Water  in  Intercellular  Spaces,  1G7 

Water  in  Protoplasm,  166 

Water  in  the  Plant,  166 

Water  Lily,  71,  128,  558 

Water  Lily  Family,  557 

Watermelon,  188,  522 

Water  of  Organization,  32,  179 

Water  Plantain,  128 

Water  Plantain  Family,  466 

Water  pores,  104 

Water  Net,  223 

Water  Weed,  473 

Wattles,  533 

Wax  Palm,  93,  464,  466 

Wax  Plant,  503 

Weeping  Trees,  196 

Weeping  Willow,  487 

Weigelia,  518 

West  India  Birch,  540 

West  India  Locust,  533 

Weld,  552 

Welwitschia,  413.  415 

Wheat,  56,  59,  98,  187,  316,  318, 

323,  428,  453 
White  Ash,  505 
White  Cedar,  41 1 
White  Clover,  166 
White  Elm,  488 
White  Hellebore,  459 
White  Ipecacuanha,  551 
White  Light,  192 
White  Lily,  460 
White  Mulberry,  490 
White  Mustard,  188,  554 
White  Oaks,  479 
White  Pepper.  483 
White  Pine,  412 
White  Poplar.  172 
White  Spruce,  412 
Whitlavia,  503 
Whorls  of  Leave?,  149 
Whortleberry.  64 
Wicopy,  492 
Wild  Black  Cherry,  530 
Wild  Cucumber,  522 


Willow,  04,  127,  143,  284,  486 
Willow  Family,  486 
Windsor  Bean,  474 
Winged  Seeds,  437 
Winter  Buds,  141 
Winter  Cherry,  500 
Wintergreen,  510 
Wistaria,  532 
Witch  Hazel,  526 
Wrolffia,  461 
Wood,  447 

Wood-cells,  17,  34,  173 
Wood  Fibres,  74,  119 
Wood  Nettle,  491 
Wood  Sorrel,  543 
Woorara,  503 
Wormia,  562 
Wormseed,  495 
Wormwood,  514 
Wrack,  269 
Wrangelia,  277 
Wrangeliaceae,  277 

Xanthium,  515 
Xanthorrho3a,  461 
Xanthosia,  520 
Xanthoxyleae.  542 
Xanthoxylum,  127.  132,  54i 
Xylem,  118,  201.  407 
Xylographa,  310 
Xylomites,  295 
Xylopia,  561 
Xylophylla,  485 
Xyridaceae,  457 

Yam  Family,  467 
Yeast  Plant,  17,  39,  214 
Yellow  Pine,  412 
Yellow  Poplar,  562 
Yellow  Thistle,  514 
Yew,  93,  410 
Yucca,  461 
Yuccites,  473 
Yulan  Tree,  562 

Zamia,  410 

ZamioBtrolms,  416 

Zea,  88,  102,  113,  455 

Ze.bra  Poison,  485 

Zebra  Wood,  534 

Zingiber,  472 
!  Zingiberaceae,  472 
!  Zinnia.  58,  5H 
I  Zizyphus,  53'J,  565 


GENERAL  INDEX. 


611 


Zonotricliia,  218 
Zooglcea  Stage,  212 
Zoogonidium,  221,  252 
Zoospore,  42,  66,  221,  241,  245,  271 

302 

Zoosporeae,  221,  241,  244,  269,  &J9 
Zostera,  13 
Zygnema,  51,  67,  234 


Zygnemacese,  232,  242,  336,  338 
Zygomorphic,  431 
Zygomycetes,  340 
Zygophyllacese,  543 
Zygospore,  220 

Zygosporeae,  45,  205,  220,  242,  244 
C06,  335,  336,  338,  568,  569,  570  ' 


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